xref: /aosp_15_r20/external/libxml2/nanohttp.c (revision 7c5688314b92172186c154356a6374bf7684c3ca)

/*
 * nanohttp.c: minimalist HTTP GET implementation to fetch external subsets.
 *             focuses on size, streamability, reentrancy and portability
 *
 * This is clearly not a general purpose HTTP implementation
 * If you look for one, check:
 *         http://www.w3.org/Library/
 *
 * See Copyright for the status of this software.
 *
 * [email protected]
 */

#define IN_LIBXML
#include "libxml.h"

#ifdef LIBXML_HTTP_ENABLED
#include <string.h>
#include <ctype.h>
#include <stdlib.h>
#include <errno.h>

#include <fcntl.h>

#ifdef _WIN32

#include <io.h>
#include <wsockcompat.h>
#define XML_SOCKLEN_T int

#else /* _WIN32 */

#include <netdb.h>
#include <netinet/in.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <unistd.h>

#ifdef HAVE_POLL_H
  #include <poll.h>
#else
  #include <sys/select.h>
#endif

/* This can be disabled if you don't have getaddrinfo */
#define SUPPORT_IP6
#define XML_SOCKLEN_T socklen_t

#endif /* _WIN32 */

#ifdef LIBXML_ZLIB_ENABLED
#include <zlib.h>
#endif

#include <libxml/xmlerror.h>
#include <libxml/xmlmemory.h>
#include <libxml/parser.h> /* for xmlStr(n)casecmp() */
#include <libxml/nanohttp.h>
#include <libxml/uri.h>

#include "private/error.h"
#include "private/io.h"

/**
 * A couple portability macros
 */
#ifndef _WINSOCKAPI_
#define closesocket(s) close(s)
#define SOCKET int
#define INVALID_SOCKET (-1)
#endif

#define GETHOSTBYNAME_ARG_CAST (char *)
#define SEND_ARG2_CAST (char *)

#define XML_NANO_HTTP_MAX_REDIR	10

#define XML_NANO_HTTP_CHUNK	4096

#define XML_NANO_HTTP_CLOSED	0
#define XML_NANO_HTTP_WRITE	1
#define XML_NANO_HTTP_READ	2
#define XML_NANO_HTTP_NONE	4

#define __xmlIOErr(domain, code, extra) ((void) 0)

typedef struct xmlNanoHTTPCtxt {
    char *protocol;	/* the protocol name */
    char *hostname;	/* the host name */
    int port;		/* the port */
    char *path;		/* the path within the URL */
    char *query;	/* the query string */
    SOCKET fd;		/* the file descriptor for the socket */
    int state;		/* WRITE / READ / CLOSED */
    char *out;		/* buffer sent (zero terminated) */
    char *outptr;	/* index within the buffer sent */
    char *in;		/* the receiving buffer */
    char *content;	/* the start of the content */
    char *inptr;	/* the next byte to read from network */
    char *inrptr;	/* the next byte to give back to the client */
    int inlen;		/* len of the input buffer */
    int last;		/* return code for last operation */
    int returnValue;	/* the protocol return value */
    int version;        /* the protocol version */
    int ContentLength;  /* specified content length from HTTP header */
    char *contentType;	/* the MIME type for the input */
    char *location;	/* the new URL in case of redirect */
    char *authHeader;	/* contents of {WWW,Proxy}-Authenticate header */
    char *encoding;	/* encoding extracted from the contentType */
    char *mimeType;	/* Mime-Type extracted from the contentType */
#ifdef LIBXML_ZLIB_ENABLED
    z_stream *strm;	/* Zlib stream object */
    int usesGzip;	/* "Content-Encoding: gzip" was detected */
#endif
} xmlNanoHTTPCtxt, *xmlNanoHTTPCtxtPtr;

static int initialized = 0;
static char *proxy = NULL;	 /* the proxy name if any */
static int proxyPort;	/* the proxy port if any */
static unsigned int timeout = 60;/* the select() timeout in seconds */

static int xmlNanoHTTPFetchContent( void * ctx, char ** ptr, int * len );

/**
 * xmlHTTPErrMemory:
 * @extra:  extra information
 *
 * Handle an out of memory condition
 */
static void
xmlHTTPErrMemory(void)
{
    xmlRaiseMemoryError(NULL, NULL, NULL, XML_FROM_HTTP, NULL);
}

/**
 * A portability function
 */
static int socket_errno(void) {
#ifdef _WINSOCKAPI_
    int err = WSAGetLastError();
    switch(err) {
        case WSAECONNRESET:
            return(ECONNRESET);
        case WSAEINPROGRESS:
            return(EINPROGRESS);
        case WSAEINTR:
            return(EINTR);
        case WSAESHUTDOWN:
            return(ESHUTDOWN);
        case WSAEWOULDBLOCK:
            return(EWOULDBLOCK);
        default:
            return(err);
    }
#else
    return(errno);
#endif
}

/**
 * xmlNanoHTTPInit:
 *
 * Initialize the HTTP protocol layer.
 * Currently it just checks for proxy information
 */

void
xmlNanoHTTPInit(void) {
    const char *env;
#ifdef _WINSOCKAPI_
    WSADATA wsaData;
#endif

    if (initialized)
	return;

#ifdef _WINSOCKAPI_
    if (WSAStartup(MAKEWORD(1, 1), &wsaData) != 0)
	return;
#endif

    if (proxy == NULL) {
	proxyPort = 80;
	env = getenv("no_proxy");
	if (env && ((env[0] == '*') && (env[1] == 0)))
	    goto done;
	env = getenv("http_proxy");
	if (env != NULL) {
	    xmlNanoHTTPScanProxy(env);
	    goto done;
	}
	env = getenv("HTTP_PROXY");
	if (env != NULL) {
	    xmlNanoHTTPScanProxy(env);
	    goto done;
	}
    }
done:
    initialized = 1;
}

/**
 * xmlNanoHTTPCleanup:
 *
 * Cleanup the HTTP protocol layer.
 */

void
xmlNanoHTTPCleanup(void) {
    if (proxy != NULL) {
	xmlFree(proxy);
	proxy = NULL;
    }
#ifdef _WINSOCKAPI_
    if (initialized)
	WSACleanup();
#endif
    initialized = 0;
    return;
}

/**
 * xmlNanoHTTPScanURL:
 * @ctxt:  an HTTP context
 * @URL:  The URL used to initialize the context
 *
 * (Re)Initialize an HTTP context by parsing the URL and finding
 * the protocol host port and path it indicates.
 */

static void
xmlNanoHTTPScanURL(xmlNanoHTTPCtxtPtr ctxt, const char *URL) {
    xmlURIPtr uri;
    int len;

    /*
     * Clear any existing data from the context
     */
    if (ctxt->protocol != NULL) {
        xmlFree(ctxt->protocol);
	ctxt->protocol = NULL;
    }
    if (ctxt->hostname != NULL) {
        xmlFree(ctxt->hostname);
	ctxt->hostname = NULL;
    }
    if (ctxt->path != NULL) {
        xmlFree(ctxt->path);
	ctxt->path = NULL;
    }
    if (ctxt->query != NULL) {
        xmlFree(ctxt->query);
	ctxt->query = NULL;
    }
    if (URL == NULL) return;

    uri = xmlParseURIRaw(URL, 1);
    if (uri == NULL)
	return;

    if ((uri->scheme == NULL) || (uri->server == NULL)) {
	xmlFreeURI(uri);
	return;
    }

    ctxt->protocol = xmlMemStrdup(uri->scheme);
    /* special case of IPv6 addresses, the [] need to be removed */
    if ((uri->server != NULL) && (*uri->server == '[')) {
        len = strlen(uri->server);
	if ((len > 2) && (uri->server[len - 1] == ']')) {
	    ctxt->hostname = (char *) xmlCharStrndup(uri->server + 1, len -2);
	} else
	    ctxt->hostname = xmlMemStrdup(uri->server);
    } else
	ctxt->hostname = xmlMemStrdup(uri->server);
    if (uri->path != NULL)
	ctxt->path = xmlMemStrdup(uri->path);
    else
	ctxt->path = xmlMemStrdup("/");
    if (uri->query != NULL)
	ctxt->query = xmlMemStrdup(uri->query);
    if (uri->port != 0)
	ctxt->port = uri->port;

    xmlFreeURI(uri);
}

/**
 * xmlNanoHTTPScanProxy:
 * @URL:  The proxy URL used to initialize the proxy context
 *
 * (Re)Initialize the HTTP Proxy context by parsing the URL and finding
 * the protocol host port it indicates.
 * Should be like http://myproxy/ or http://myproxy:3128/
 * A NULL URL cleans up proxy information.
 */

void
xmlNanoHTTPScanProxy(const char *URL) {
    xmlURIPtr uri;

    if (proxy != NULL) {
        xmlFree(proxy);
	proxy = NULL;
    }
    proxyPort = 0;

    if (URL == NULL) return;

    uri = xmlParseURIRaw(URL, 1);
    if ((uri == NULL) || (uri->scheme == NULL) ||
	(strcmp(uri->scheme, "http")) || (uri->server == NULL)) {
	__xmlIOErr(XML_FROM_HTTP, XML_HTTP_URL_SYNTAX, "Syntax Error\n");
	if (uri != NULL)
	    xmlFreeURI(uri);
	return;
    }

    proxy = xmlMemStrdup(uri->server);
    if (uri->port != 0)
	proxyPort = uri->port;

    xmlFreeURI(uri);
}

/**
 * xmlNanoHTTPNewCtxt:
 * @URL:  The URL used to initialize the context
 *
 * Allocate and initialize a new HTTP context.
 *
 * Returns an HTTP context or NULL in case of error.
 */

static xmlNanoHTTPCtxtPtr
xmlNanoHTTPNewCtxt(const char *URL) {
    xmlNanoHTTPCtxtPtr ret;

    ret = (xmlNanoHTTPCtxtPtr) xmlMalloc(sizeof(xmlNanoHTTPCtxt));
    if (ret == NULL) {
        xmlHTTPErrMemory();
        return(NULL);
    }

    memset(ret, 0, sizeof(xmlNanoHTTPCtxt));
    ret->port = 80;
    ret->returnValue = 0;
    ret->fd = INVALID_SOCKET;
    ret->ContentLength = -1;

    xmlNanoHTTPScanURL(ret, URL);

    return(ret);
}

/**
 * xmlNanoHTTPFreeCtxt:
 * @ctxt:  an HTTP context
 *
 * Frees the context after closing the connection.
 */

static void
xmlNanoHTTPFreeCtxt(xmlNanoHTTPCtxtPtr ctxt) {
    if (ctxt == NULL) return;
    if (ctxt->hostname != NULL) xmlFree(ctxt->hostname);
    if (ctxt->protocol != NULL) xmlFree(ctxt->protocol);
    if (ctxt->path != NULL) xmlFree(ctxt->path);
    if (ctxt->query != NULL) xmlFree(ctxt->query);
    if (ctxt->out != NULL) xmlFree(ctxt->out);
    if (ctxt->in != NULL) xmlFree(ctxt->in);
    if (ctxt->contentType != NULL) xmlFree(ctxt->contentType);
    if (ctxt->encoding != NULL) xmlFree(ctxt->encoding);
    if (ctxt->mimeType != NULL) xmlFree(ctxt->mimeType);
    if (ctxt->location != NULL) xmlFree(ctxt->location);
    if (ctxt->authHeader != NULL) xmlFree(ctxt->authHeader);
#ifdef LIBXML_ZLIB_ENABLED
    if (ctxt->strm != NULL) {
	inflateEnd(ctxt->strm);
	xmlFree(ctxt->strm);
    }
#endif

    ctxt->state = XML_NANO_HTTP_NONE;
    if (ctxt->fd != INVALID_SOCKET) closesocket(ctxt->fd);
    ctxt->fd = INVALID_SOCKET;
    xmlFree(ctxt);
}

/**
 * xmlNanoHTTPSend:
 * @ctxt:  an HTTP context
 *
 * Send the input needed to initiate the processing on the server side
 * Returns number of bytes sent or -1 on error.
 */

static int
xmlNanoHTTPSend(xmlNanoHTTPCtxtPtr ctxt, const char *xmt_ptr, int outlen)
{
    int total_sent = 0;
#ifdef HAVE_POLL_H
    struct pollfd p;
#else
    struct timeval tv;
    fd_set wfd;
#endif

    if ((ctxt->state & XML_NANO_HTTP_WRITE) && (xmt_ptr != NULL)) {
        while (total_sent < outlen) {
            int nsent = send(ctxt->fd, SEND_ARG2_CAST (xmt_ptr + total_sent),
                             outlen - total_sent, 0);

            if (nsent > 0)
                total_sent += nsent;
            else if ((nsent == -1) &&
#if defined(EAGAIN) && EAGAIN != EWOULDBLOCK
                     (socket_errno() != EAGAIN) &&
#endif
                     (socket_errno() != EWOULDBLOCK)) {
                __xmlIOErr(XML_FROM_HTTP, 0, "send failed\n");
                if (total_sent == 0)
                    total_sent = -1;
                break;
            } else {
                /*
                 * No data sent
                 * Since non-blocking sockets are used, wait for
                 * socket to be writable or default timeout prior
                 * to retrying.
                 */
#ifndef HAVE_POLL_H
#ifndef _WINSOCKAPI_
                if (ctxt->fd > FD_SETSIZE)
                    return -1;
#endif

                tv.tv_sec = timeout;
                tv.tv_usec = 0;
                FD_ZERO(&wfd);
#ifdef _MSC_VER
#pragma warning(push)
#pragma warning(disable: 4018)
#endif
                FD_SET(ctxt->fd, &wfd);
#ifdef _MSC_VER
#pragma warning(pop)
#endif
                (void) select(ctxt->fd + 1, NULL, &wfd, NULL, &tv);
#else
                p.fd = ctxt->fd;
                p.events = POLLOUT;
                (void) poll(&p, 1, timeout * 1000);
#endif /* !HAVE_POLL_H */
            }
        }
    }

    return total_sent;
}

/**
 * xmlNanoHTTPRecv:
 * @ctxt:  an HTTP context
 *
 * Read information coming from the HTTP connection.
 * This is a blocking call (but it blocks in select(), not read()).
 *
 * Returns the number of byte read or -1 in case of error.
 */

static int
xmlNanoHTTPRecv(xmlNanoHTTPCtxtPtr ctxt)
{
#ifdef HAVE_POLL_H
    struct pollfd p;
#else
    fd_set rfd;
    struct timeval tv;
#endif


    while (ctxt->state & XML_NANO_HTTP_READ) {
        if (ctxt->in == NULL) {
            ctxt->in = xmlMalloc(65000);
            if (ctxt->in == NULL) {
                xmlHTTPErrMemory();
                ctxt->last = -1;
                return (-1);
            }
            ctxt->inlen = 65000;
            ctxt->inptr = ctxt->content = ctxt->inrptr = ctxt->in;
        }
        if (ctxt->inrptr > ctxt->in + XML_NANO_HTTP_CHUNK) {
            int delta = ctxt->inrptr - ctxt->in;
            int len = ctxt->inptr - ctxt->inrptr;

            memmove(ctxt->in, ctxt->inrptr, len);
            ctxt->inrptr -= delta;
            ctxt->content -= delta;
            ctxt->inptr -= delta;
        }
        if ((ctxt->in + ctxt->inlen) < (ctxt->inptr + XML_NANO_HTTP_CHUNK)) {
            int d_inptr = ctxt->inptr - ctxt->in;
            int d_content = ctxt->content - ctxt->in;
            int d_inrptr = ctxt->inrptr - ctxt->in;
            char *tmp_ptr = ctxt->in;

            ctxt->inlen *= 2;
            ctxt->in = (char *) xmlRealloc(tmp_ptr, ctxt->inlen);
            if (ctxt->in == NULL) {
                xmlHTTPErrMemory();
                xmlFree(tmp_ptr);
                ctxt->last = -1;
                return (-1);
            }
            ctxt->inptr = ctxt->in + d_inptr;
            ctxt->content = ctxt->in + d_content;
            ctxt->inrptr = ctxt->in + d_inrptr;
        }
        ctxt->last = recv(ctxt->fd, ctxt->inptr, XML_NANO_HTTP_CHUNK, 0);
        if (ctxt->last > 0) {
            ctxt->inptr += ctxt->last;
            return (ctxt->last);
        }
        if (ctxt->last == 0) {
            return (0);
        }
        if (ctxt->last == -1) {
            switch (socket_errno()) {
                case EINPROGRESS:
                case EWOULDBLOCK:
#if defined(EAGAIN) && EAGAIN != EWOULDBLOCK
                case EAGAIN:
#endif
                    break;

                case ECONNRESET:
                case ESHUTDOWN:
                    return (0);

                default:
                    __xmlIOErr(XML_FROM_HTTP, 0, "recv failed\n");
                    return (-1);
            }
        }
#ifdef HAVE_POLL_H
        p.fd = ctxt->fd;
        p.events = POLLIN;
        if ((poll(&p, 1, timeout * 1000) < 1)
#if defined(EINTR)
            && (errno != EINTR)
#endif
            )
            return (0);
#else /* !HAVE_POLL_H */
#ifndef _WINSOCKAPI_
        if (ctxt->fd > FD_SETSIZE)
            return 0;
#endif

        tv.tv_sec = timeout;
        tv.tv_usec = 0;
        FD_ZERO(&rfd);

#ifdef _MSC_VER
#pragma warning(push)
#pragma warning(disable: 4018)
#endif

        FD_SET(ctxt->fd, &rfd);

#ifdef _MSC_VER
#pragma warning(pop)
#endif

        if ((select(ctxt->fd + 1, &rfd, NULL, NULL, &tv) < 1)
#if defined(EINTR)
            && (socket_errno() != EINTR)
#endif
            )
            return (0);
#endif /* !HAVE_POLL_H */
    }
    return (0);
}

/**
 * xmlNanoHTTPReadLine:
 * @ctxt:  an HTTP context
 *
 * Read one line in the HTTP server output, usually for extracting
 * the HTTP protocol information from the answer header.
 *
 * Returns a newly allocated string with a copy of the line, or NULL
 *         which indicate the end of the input.
 */

static char *
xmlNanoHTTPReadLine(xmlNanoHTTPCtxtPtr ctxt) {
    char buf[4096];
    char *bp = buf;
    int	rc;

    while (bp - buf < 4095) {
	if (ctxt->inrptr == ctxt->inptr) {
	    if ( (rc = xmlNanoHTTPRecv(ctxt)) == 0) {
		if (bp == buf)
		    return(NULL);
		else
		    *bp = 0;
		return(xmlMemStrdup(buf));
	    }
	    else if ( rc == -1 ) {
	        return ( NULL );
	    }
	}
	*bp = *ctxt->inrptr++;
	if (*bp == '\n') {
	    *bp = 0;
	    return(xmlMemStrdup(buf));
	}
	if (*bp != '\r')
	    bp++;
    }
    buf[4095] = 0;
    return(xmlMemStrdup(buf));
}


/**
 * xmlNanoHTTPScanAnswer:
 * @ctxt:  an HTTP context
 * @line:  an HTTP header line
 *
 * Try to extract useful information from the server answer.
 * We currently parse and process:
 *  - The HTTP revision/ return code
 *  - The Content-Type, Mime-Type and charset used
 *  - The Location for redirect processing.
 *
 * Returns -1 in case of failure, the file descriptor number otherwise
 */

static void
xmlNanoHTTPScanAnswer(xmlNanoHTTPCtxtPtr ctxt, const char *line) {
    const char *cur = line;

    if (line == NULL) return;

    if (!strncmp(line, "HTTP/", 5)) {
        int version = 0;
	int ret = 0;

	cur += 5;
	while ((*cur >= '0') && (*cur <= '9')) {
	    version *= 10;
	    version += *cur - '0';
	    cur++;
	}
	if (*cur == '.') {
	    cur++;
	    if ((*cur >= '0') && (*cur <= '9')) {
		version *= 10;
		version += *cur - '0';
		cur++;
	    }
	    while ((*cur >= '0') && (*cur <= '9'))
		cur++;
	} else
	    version *= 10;
	if ((*cur != ' ') && (*cur != '\t')) return;
	while ((*cur == ' ') || (*cur == '\t')) cur++;
	if ((*cur < '0') || (*cur > '9')) return;
	while ((*cur >= '0') && (*cur <= '9')) {
	    ret *= 10;
	    ret += *cur - '0';
	    cur++;
	}
	if ((*cur != 0) && (*cur != ' ') && (*cur != '\t')) return;
	ctxt->returnValue = ret;
        ctxt->version = version;
    } else if (!xmlStrncasecmp(BAD_CAST line, BAD_CAST"Content-Type:", 13)) {
        const xmlChar *charset, *last, *mime;
        cur += 13;
	while ((*cur == ' ') || (*cur == '\t')) cur++;
	if (ctxt->contentType != NULL)
	    xmlFree(ctxt->contentType);
	ctxt->contentType = xmlMemStrdup(cur);
	mime = (const xmlChar *) cur;
	last = mime;
	while ((*last != 0) && (*last != ' ') && (*last != '\t') &&
	       (*last != ';') && (*last != ','))
	    last++;
	if (ctxt->mimeType != NULL)
	    xmlFree(ctxt->mimeType);
	ctxt->mimeType = (char *) xmlStrndup(mime, last - mime);
	charset = xmlStrstr(BAD_CAST ctxt->contentType, BAD_CAST "charset=");
	if (charset != NULL) {
	    charset += 8;
	    last = charset;
	    while ((*last != 0) && (*last != ' ') && (*last != '\t') &&
	           (*last != ';') && (*last != ','))
		last++;
	    if (ctxt->encoding != NULL)
	        xmlFree(ctxt->encoding);
	    ctxt->encoding = (char *) xmlStrndup(charset, last - charset);
	}
    } else if (!xmlStrncasecmp(BAD_CAST line, BAD_CAST"ContentType:", 12)) {
        const xmlChar *charset, *last, *mime;
        cur += 12;
	if (ctxt->contentType != NULL) return;
	while ((*cur == ' ') || (*cur == '\t')) cur++;
	ctxt->contentType = xmlMemStrdup(cur);
	mime = (const xmlChar *) cur;
	last = mime;
	while ((*last != 0) && (*last != ' ') && (*last != '\t') &&
	       (*last != ';') && (*last != ','))
	    last++;
	if (ctxt->mimeType != NULL)
	    xmlFree(ctxt->mimeType);
	ctxt->mimeType = (char *) xmlStrndup(mime, last - mime);
	charset = xmlStrstr(BAD_CAST ctxt->contentType, BAD_CAST "charset=");
	if (charset != NULL) {
	    charset += 8;
	    last = charset;
	    while ((*last != 0) && (*last != ' ') && (*last != '\t') &&
	           (*last != ';') && (*last != ','))
		last++;
	    if (ctxt->encoding != NULL)
	        xmlFree(ctxt->encoding);
	    ctxt->encoding = (char *) xmlStrndup(charset, last - charset);
	}
    } else if (!xmlStrncasecmp(BAD_CAST line, BAD_CAST"Location:", 9)) {
        cur += 9;
	while ((*cur == ' ') || (*cur == '\t')) cur++;
	if (ctxt->location != NULL)
	    xmlFree(ctxt->location);
	if (*cur == '/') {
	    xmlChar *tmp_http = xmlStrdup(BAD_CAST "http://");
	    xmlChar *tmp_loc =
	        xmlStrcat(tmp_http, (const xmlChar *) ctxt->hostname);
	    ctxt->location =
	        (char *) xmlStrcat (tmp_loc, (const xmlChar *) cur);
	} else {
	    ctxt->location = xmlMemStrdup(cur);
	}
    } else if (!xmlStrncasecmp(BAD_CAST line, BAD_CAST"WWW-Authenticate:", 17)) {
        cur += 17;
	while ((*cur == ' ') || (*cur == '\t')) cur++;
	if (ctxt->authHeader != NULL)
	    xmlFree(ctxt->authHeader);
	ctxt->authHeader = xmlMemStrdup(cur);
    } else if (!xmlStrncasecmp(BAD_CAST line, BAD_CAST"Proxy-Authenticate:", 19)) {
        cur += 19;
	while ((*cur == ' ') || (*cur == '\t')) cur++;
	if (ctxt->authHeader != NULL)
	    xmlFree(ctxt->authHeader);
	ctxt->authHeader = xmlMemStrdup(cur);
#ifdef LIBXML_ZLIB_ENABLED
    } else if ( !xmlStrncasecmp( BAD_CAST line, BAD_CAST"Content-Encoding:", 17) ) {
	cur += 17;
	while ((*cur == ' ') || (*cur == '\t')) cur++;
	if ( !xmlStrncasecmp( BAD_CAST cur, BAD_CAST"gzip", 4) ) {
	    ctxt->usesGzip = 1;

	    ctxt->strm = xmlMalloc(sizeof(z_stream));

	    if (ctxt->strm != NULL) {
		ctxt->strm->zalloc = Z_NULL;
		ctxt->strm->zfree = Z_NULL;
		ctxt->strm->opaque = Z_NULL;
		ctxt->strm->avail_in = 0;
		ctxt->strm->next_in = Z_NULL;

		inflateInit2( ctxt->strm, 31 );
	    }
	}
#endif
    } else if ( !xmlStrncasecmp( BAD_CAST line, BAD_CAST"Content-Length:", 15) ) {
	cur += 15;
	ctxt->ContentLength = strtol( cur, NULL, 10 );
    }
}

/**
 * xmlNanoHTTPConnectAttempt:
 * @addr:  a socket address structure
 *
 * Attempt a connection to the given IP:port endpoint. It forces
 * non-blocking semantic on the socket, and allow 60 seconds for
 * the host to answer.
 *
 * Returns -1 in case of failure, the file descriptor number otherwise
 */

static SOCKET
xmlNanoHTTPConnectAttempt(struct sockaddr *addr)
{
#ifndef HAVE_POLL_H
    fd_set wfd;
#ifdef _WINSOCKAPI_
    fd_set xfd;
#endif
    struct timeval tv;
#else /* !HAVE_POLL_H */
    struct pollfd p;
#endif /* !HAVE_POLL_H */
    int status;

    int addrlen;

    SOCKET s;

#ifdef SUPPORT_IP6
    if (addr->sa_family == AF_INET6) {
        s = socket(PF_INET6, SOCK_STREAM, IPPROTO_TCP);
        addrlen = sizeof(struct sockaddr_in6);
    } else
#endif
    {
        s = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
        addrlen = sizeof(struct sockaddr_in);
    }
    if (s == INVALID_SOCKET) {
        __xmlIOErr(XML_FROM_HTTP, 0, "socket failed\n");
        return INVALID_SOCKET;
    }
#ifdef _WINSOCKAPI_
    {
        u_long one = 1;

        status = ioctlsocket(s, FIONBIO, &one) == SOCKET_ERROR ? -1 : 0;
    }
#else /* _WINSOCKAPI_ */
#if defined(VMS)
    {
        int enable = 1;

        status = ioctl(s, FIONBIO, &enable);
    }
#else /* VMS */
    if ((status = fcntl(s, F_GETFL, 0)) != -1) {
#ifdef O_NONBLOCK
        status |= O_NONBLOCK;
#else /* O_NONBLOCK */
#ifdef F_NDELAY
        status |= F_NDELAY;
#endif /* F_NDELAY */
#endif /* !O_NONBLOCK */
        status = fcntl(s, F_SETFL, status);
    }
    if (status < 0) {
        __xmlIOErr(XML_FROM_HTTP, 0, "error setting non-blocking IO\n");
        closesocket(s);
        return INVALID_SOCKET;
    }
#endif /* !VMS */
#endif /* !_WINSOCKAPI_ */

    if (connect(s, addr, addrlen) == -1) {
        switch (socket_errno()) {
            case EINPROGRESS:
            case EWOULDBLOCK:
                break;
            default:
                __xmlIOErr(XML_FROM_HTTP, 0,
                           "error connecting to HTTP server");
                closesocket(s);
                return INVALID_SOCKET;
        }
    }
#ifndef HAVE_POLL_H
    tv.tv_sec = timeout;
    tv.tv_usec = 0;

#ifdef _MSC_VER
#pragma warning(push)
#pragma warning(disable: 4018)
#endif
#ifndef _WINSOCKAPI_
    if (s > FD_SETSIZE)
        return INVALID_SOCKET;
#endif
    FD_ZERO(&wfd);
    FD_SET(s, &wfd);

#ifdef _WINSOCKAPI_
    FD_ZERO(&xfd);
    FD_SET(s, &xfd);

    switch (select(s + 1, NULL, &wfd, &xfd, &tv))
#else
    switch (select(s + 1, NULL, &wfd, NULL, &tv))
#endif
#ifdef _MSC_VER
#pragma warning(pop)
#endif

#else /* !HAVE_POLL_H */
    p.fd = s;
    p.events = POLLOUT;
    switch (poll(&p, 1, timeout * 1000))
#endif /* !HAVE_POLL_H */

    {
        case 0:
            /* Time out */
            __xmlIOErr(XML_FROM_HTTP, 0, "Connect attempt timed out");
            closesocket(s);
            return INVALID_SOCKET;
        case -1:
            /* Ermm.. ?? */
            __xmlIOErr(XML_FROM_HTTP, 0, "Connect failed");
            closesocket(s);
            return INVALID_SOCKET;
    }

#ifndef HAVE_POLL_H
    if (FD_ISSET(s, &wfd)
#ifdef _WINSOCKAPI_
        || FD_ISSET(s, &xfd)
#endif
        )
#else /* !HAVE_POLL_H */
    if (p.revents == POLLOUT)
#endif /* !HAVE_POLL_H */
    {
        XML_SOCKLEN_T len;

        len = sizeof(status);
#ifdef SO_ERROR
        if (getsockopt(s, SOL_SOCKET, SO_ERROR, (char *) &status, &len) <
            0) {
            /* Solaris error code */
            __xmlIOErr(XML_FROM_HTTP, 0, "getsockopt failed\n");
            closesocket(s);
            return INVALID_SOCKET;
        }
#endif
        if (status) {
            __xmlIOErr(XML_FROM_HTTP, 0,
                       "Error connecting to remote host");
            closesocket(s);
            errno = status;
            return INVALID_SOCKET;
        }
    } else {
        /* pbm */
        __xmlIOErr(XML_FROM_HTTP, 0, "select failed\n");
        closesocket(s);
        return INVALID_SOCKET;
    }

    return (s);
}

/**
 * xmlNanoHTTPConnectHost:
 * @host:  the host name
 * @port:  the port number
 *
 * Attempt a connection to the given host:port endpoint. It tries
 * the multiple IP provided by the DNS if available.
 *
 * Returns -1 in case of failure, the file descriptor number otherwise
 */

static SOCKET
xmlNanoHTTPConnectHost(const char *host, int port)
{
    struct sockaddr *addr = NULL;
    struct sockaddr_in sockin;

#ifdef SUPPORT_IP6
    struct sockaddr_in6 sockin6;
#endif
    SOCKET s;

    memset (&sockin, 0, sizeof(sockin));

#if defined(SUPPORT_IP6)
    {
	int status;
	struct addrinfo hints, *res, *result;

        memset (&sockin6, 0, sizeof(sockin6));

	result = NULL;
	memset (&hints, 0,sizeof(hints));
	hints.ai_socktype = SOCK_STREAM;

	status = getaddrinfo (host, NULL, &hints, &result);
	if (status) {
	    __xmlIOErr(XML_FROM_HTTP, 0, "getaddrinfo failed\n");
	    return INVALID_SOCKET;
	}

	for (res = result; res; res = res->ai_next) {
	    if (res->ai_family == AF_INET) {
		if ((size_t)res->ai_addrlen > sizeof(sockin)) {
		    __xmlIOErr(XML_FROM_HTTP, 0, "address size mismatch\n");
		    freeaddrinfo (result);
		    return INVALID_SOCKET;
		}
		memcpy (&sockin, res->ai_addr, res->ai_addrlen);
		sockin.sin_port = htons (port);
		addr = (struct sockaddr *)&sockin;
	    } else if (res->ai_family == AF_INET6) {
		if ((size_t)res->ai_addrlen > sizeof(sockin6)) {
		    __xmlIOErr(XML_FROM_HTTP, 0, "address size mismatch\n");
		    freeaddrinfo (result);
		    return INVALID_SOCKET;
		}
		memcpy (&sockin6, res->ai_addr, res->ai_addrlen);
		sockin6.sin6_port = htons (port);
		addr = (struct sockaddr *)&sockin6;
	    } else
		continue;              /* for */

	    s = xmlNanoHTTPConnectAttempt (addr);
	    if (s != INVALID_SOCKET) {
		freeaddrinfo (result);
		return (s);
	    }
	}

	if (result)
	    freeaddrinfo (result);
    }
#else
    {
        struct hostent *h;
        struct in_addr ia;
        int i;

	h = gethostbyname (GETHOSTBYNAME_ARG_CAST host);
	if (h == NULL) {

/*
 * Okay, I got fed up by the non-portability of this error message
 * extraction code. it work on Linux, if it work on your platform
 * and one want to enable it, send me the defined(foobar) needed
 */
#if defined(HOST_NOT_FOUND) && defined(__linux__)
	    const char *h_err_txt = "";

	    switch (h_errno) {
		case HOST_NOT_FOUND:
		    h_err_txt = "Authoritative host not found";
		    break;

		case TRY_AGAIN:
		    h_err_txt =
			"Non-authoritative host not found or server failure.";
		    break;

		case NO_RECOVERY:
		    h_err_txt =
			"Non-recoverable errors:  FORMERR, REFUSED, or NOTIMP.";
		    break;

#ifdef NO_ADDRESS
		case NO_ADDRESS:
		    h_err_txt =
			"Valid name, no data record of requested type.";
		    break;
#endif

		default:
		    h_err_txt = "No error text defined.";
		    break;
	    }
	    __xmlIOErr(XML_FROM_HTTP, 0, h_err_txt);
#else
	    __xmlIOErr(XML_FROM_HTTP, 0, "Failed to resolve host");
#endif
	    return INVALID_SOCKET;
	}

	for (i = 0; h->h_addr_list[i]; i++) {
	    if (h->h_addrtype == AF_INET) {
		/* A records (IPv4) */
		if ((unsigned int) h->h_length > sizeof(ia)) {
		    __xmlIOErr(XML_FROM_HTTP, 0, "address size mismatch\n");
		    return INVALID_SOCKET;
		}
		memcpy (&ia, h->h_addr_list[i], h->h_length);
		sockin.sin_family = h->h_addrtype;
		sockin.sin_addr = ia;
		sockin.sin_port = (unsigned short)htons ((unsigned short)port);
		addr = (struct sockaddr *) &sockin;
	    } else
		break;              /* for */

	    s = xmlNanoHTTPConnectAttempt (addr);
	    if (s != INVALID_SOCKET)
		return (s);
	}
    }
#endif

    return INVALID_SOCKET;
}


/**
 * xmlNanoHTTPOpen:
 * @URL:  The URL to load
 * @contentType:  if available the Content-Type information will be
 *                returned at that location
 *
 * This function try to open a connection to the indicated resource
 * via HTTP GET.
 *
 * Returns NULL in case of failure, otherwise a request handler.
 *     The contentType, if provided must be freed by the caller
 */

void*
xmlNanoHTTPOpen(const char *URL, char **contentType) {
    if (contentType != NULL) *contentType = NULL;
    return(xmlNanoHTTPMethod(URL, NULL, NULL, contentType, NULL, 0));
}

/**
 * xmlNanoHTTPOpenRedir:
 * @URL:  The URL to load
 * @contentType:  if available the Content-Type information will be
 *                returned at that location
 * @redir: if available the redirected URL will be returned
 *
 * This function try to open a connection to the indicated resource
 * via HTTP GET.
 *
 * Returns NULL in case of failure, otherwise a request handler.
 *     The contentType, if provided must be freed by the caller
 */

void*
xmlNanoHTTPOpenRedir(const char *URL, char **contentType, char **redir) {
    if (contentType != NULL) *contentType = NULL;
    if (redir != NULL) *redir = NULL;
    return(xmlNanoHTTPMethodRedir(URL, NULL, NULL, contentType, redir, NULL,0));
}

/**
 * xmlNanoHTTPRead:
 * @ctx:  the HTTP context
 * @dest:  a buffer
 * @len:  the buffer length
 *
 * This function tries to read @len bytes from the existing HTTP connection
 * and saves them in @dest. This is a blocking call.
 *
 * Returns the number of byte read. 0 is an indication of an end of connection.
 *         -1 indicates a parameter error.
 */
int
xmlNanoHTTPRead(void *ctx, void *dest, int len) {
    xmlNanoHTTPCtxtPtr ctxt = (xmlNanoHTTPCtxtPtr) ctx;
#ifdef LIBXML_ZLIB_ENABLED
    int bytes_read = 0;
    int orig_avail_in;
    int z_ret;
#endif

    if (ctx == NULL) return(-1);
    if (dest == NULL) return(-1);
    if (len <= 0) return(0);

#ifdef LIBXML_ZLIB_ENABLED
    if (ctxt->usesGzip == 1) {
        if (ctxt->strm == NULL) return(0);

        ctxt->strm->next_out = dest;
        ctxt->strm->avail_out = len;
	ctxt->strm->avail_in = ctxt->inptr - ctxt->inrptr;

        while (ctxt->strm->avail_out > 0 &&
	       (ctxt->strm->avail_in > 0 || xmlNanoHTTPRecv(ctxt) > 0)) {
            orig_avail_in = ctxt->strm->avail_in =
			    ctxt->inptr - ctxt->inrptr - bytes_read;
            ctxt->strm->next_in = BAD_CAST (ctxt->inrptr + bytes_read);

            z_ret = inflate(ctxt->strm, Z_NO_FLUSH);
            bytes_read += orig_avail_in - ctxt->strm->avail_in;

            if (z_ret != Z_OK) break;
	}

        ctxt->inrptr += bytes_read;
        return(len - ctxt->strm->avail_out);
    }
#endif

    while (ctxt->inptr - ctxt->inrptr < len) {
        if (xmlNanoHTTPRecv(ctxt) <= 0) break;
    }
    if (ctxt->inptr - ctxt->inrptr < len)
        len = ctxt->inptr - ctxt->inrptr;
    if (len > 0) {
        memcpy(dest, ctxt->inrptr, len);
        ctxt->inrptr += len;
    }
    return(len);
}

/**
 * xmlNanoHTTPClose:
 * @ctx:  the HTTP context
 *
 * This function closes an HTTP context, it ends up the connection and
 * free all data related to it.
 */
void
xmlNanoHTTPClose(void *ctx) {
    xmlNanoHTTPCtxtPtr ctxt = (xmlNanoHTTPCtxtPtr) ctx;

    if (ctx == NULL) return;

    xmlNanoHTTPFreeCtxt(ctxt);
}


/**
 * xmlNanoHTTPHostnameMatch:
 * @pattern: The pattern as it appears in no_proxy environment variable
 * @hostname: The hostname to test as it appears in the URL
 *
 * This function tests whether a given hostname matches a pattern. The pattern
 * usually is a token from the no_proxy environment variable. Wildcards in the
 * pattern are not supported.
 *
 * Returns true, iff hostname matches the pattern.
 */

static int
xmlNanoHTTPHostnameMatch(const char *pattern, const char *hostname) {
    int idx_pattern, idx_hostname;
    const char * pattern_start;

    if (!pattern || *pattern == '\0' || !hostname)
	return 0;

    /* Ignore trailing '.' */
    if (*pattern == '.') {
        idx_pattern = strlen(pattern) -1;
        pattern_start = pattern + 1;
    }
    else {
        idx_pattern = strlen(pattern);
        pattern_start = pattern;
    }
    idx_hostname = strlen(hostname);

    for (; idx_pattern >= 0 && idx_hostname >= 0;
           --idx_pattern, --idx_hostname) {
	if (tolower((unsigned char)pattern_start[idx_pattern]) !=
            tolower((unsigned char)hostname[idx_hostname]))
	    break;
    }

    return idx_pattern == -1 && (idx_hostname == -1|| hostname[idx_hostname] == '.');
}


/**
 * xmlNanoHTTPBypassProxy:
 * @hostname: The hostname as it appears in the URL
 *
 * This function evaluates the no_proxy environment variable and returns
 * whether the proxy server should be bypassed for a given host.
 *
 * Returns true, iff a proxy server should be bypassed for the given hostname.
 */

static int
xmlNanoHTTPBypassProxy(const char *hostname) {
    size_t envlen;
    char *env = getenv("no_proxy"), *cpy=NULL, *p=NULL;
    if (!env)
	return 0;

    /* (Avoid strdup because it's not portable.) */
    envlen = strlen(env) + 1;
    cpy = xmlMalloc(envlen);
    memcpy(cpy, env, envlen);
    env = cpy;

    /* The remainder of the function is basically a tokenizing: */
    while (isspace((unsigned char)*env))
    	++env;
    if (*env == '\0') {
    	xmlFree(cpy);
	return 0;
    }

    p = env;
    while (*env) {

    	if (*env != ',') {
	    ++env;
	    continue;
	}

	*(env++) = '\0';
	if (xmlNanoHTTPHostnameMatch(p, hostname)) {
	    xmlFree(cpy);
	    return 1;
	}

	while (isspace((unsigned char)*env))
	    ++env;
	p = env;
    }
    if (xmlNanoHTTPHostnameMatch(p, hostname)) {
    	xmlFree(cpy);
    	return 1;
    }

    xmlFree(cpy);
    return 0;
}


/**
 * xmlNanoHTTPMethodRedir:
 * @URL:  The URL to load
 * @method:  the HTTP method to use
 * @input:  the input string if any
 * @contentType:  the Content-Type information IN and OUT
 * @redir:  the redirected URL OUT
 * @headers:  the extra headers
 * @ilen:  input length
 *
 * This function try to open a connection to the indicated resource
 * via HTTP using the given @method, adding the given extra headers
 * and the input buffer for the request content.
 *
 * Returns NULL in case of failure, otherwise a request handler.
 *     The contentType, or redir, if provided must be freed by the caller
 */

void*
xmlNanoHTTPMethodRedir(const char *URL, const char *method, const char *input,
                  char **contentType, char **redir,
		  const char *headers, int ilen ) {
    xmlNanoHTTPCtxtPtr ctxt;
    char *bp, *p;
    int blen;
    SOCKET ret;
    int nbRedirects = 0;
    int use_proxy;
    char *redirURL = NULL;

    if (URL == NULL) return(NULL);
    if (method == NULL) method = "GET";
    xmlNanoHTTPInit();

retry:
    if (redirURL == NULL) {
	ctxt = xmlNanoHTTPNewCtxt(URL);
	if (ctxt == NULL)
	    return(NULL);
    } else {
	ctxt = xmlNanoHTTPNewCtxt(redirURL);
	if (ctxt == NULL)
	    return(NULL);
	ctxt->location = xmlMemStrdup(redirURL);
    }

    if ((ctxt->protocol == NULL) || (strcmp(ctxt->protocol, "http"))) {
	__xmlIOErr(XML_FROM_IO, XML_IO_UNSUPPORTED_PROTOCOL, ctxt->protocol);
        xmlNanoHTTPFreeCtxt(ctxt);
	if (redirURL != NULL) xmlFree(redirURL);
        return(NULL);
    }
    if (ctxt->hostname == NULL) {
	__xmlIOErr(XML_FROM_HTTP, XML_HTTP_UNKNOWN_HOST,
	           "Failed to identify host in URI");
        xmlNanoHTTPFreeCtxt(ctxt);
	if (redirURL != NULL) xmlFree(redirURL);
        return(NULL);
    }
    use_proxy = proxy && !xmlNanoHTTPBypassProxy(ctxt->hostname);
    if (use_proxy) {
	blen = strlen(ctxt->hostname) * 2 + 16;
	ret = xmlNanoHTTPConnectHost(proxy, proxyPort);
    }
    else {
	blen = strlen(ctxt->hostname);
	ret = xmlNanoHTTPConnectHost(ctxt->hostname, ctxt->port);
    }
    if (ret == INVALID_SOCKET) {
        xmlNanoHTTPFreeCtxt(ctxt);
	if (redirURL != NULL) xmlFree(redirURL);
        return(NULL);
    }
    ctxt->fd = ret;

    if (input == NULL)
	ilen = 0;
    else
	blen += 36;

    if (headers != NULL)
	blen += strlen(headers) + 2;
    if (contentType && *contentType)
	/* reserve for string plus 'Content-Type: \r\n" */
	blen += strlen(*contentType) + 16;
    if (ctxt->query != NULL)
	/* 1 for '?' */
	blen += strlen(ctxt->query) + 1;
    blen += strlen(method) + strlen(ctxt->path) + 24;
#ifdef LIBXML_ZLIB_ENABLED
    /* reserve for possible 'Accept-Encoding: gzip' string */
    blen += 23;
#endif
    if (ctxt->port != 80) {
	/* reserve space for ':xxxxx', incl. potential proxy */
	if (use_proxy)
	    blen += 17;
	else
	    blen += 11;
    }
    bp = xmlMalloc(blen);
    if ( bp == NULL ) {
        xmlNanoHTTPFreeCtxt( ctxt );
	xmlHTTPErrMemory();
	return ( NULL );
    }

    p = bp;

    if (use_proxy) {
	if (ctxt->port != 80) {
	    p += snprintf( p, blen - (p - bp), "%s http://%s:%d%s",
			method, ctxt->hostname,
			ctxt->port, ctxt->path );
	}
	else
	    p += snprintf( p, blen - (p - bp), "%s http://%s%s", method,
			ctxt->hostname, ctxt->path);
    }
    else
	p += snprintf( p, blen - (p - bp), "%s %s", method, ctxt->path);

    if (ctxt->query != NULL)
	p += snprintf( p, blen - (p - bp), "?%s", ctxt->query);

    if (ctxt->port == 80) {
        p += snprintf( p, blen - (p - bp), " HTTP/1.0\r\nHost: %s\r\n",
		    ctxt->hostname);
    } else {
        p += snprintf( p, blen - (p - bp), " HTTP/1.0\r\nHost: %s:%d\r\n",
		    ctxt->hostname, ctxt->port);
    }

#ifdef LIBXML_ZLIB_ENABLED
    p += snprintf(p, blen - (p - bp), "Accept-Encoding: gzip\r\n");
#endif

    if (contentType != NULL && *contentType)
	p += snprintf(p, blen - (p - bp), "Content-Type: %s\r\n", *contentType);

    if (headers != NULL)
	p += snprintf( p, blen - (p - bp), "%s", headers );

    if (input != NULL)
	snprintf(p, blen - (p - bp), "Content-Length: %d\r\n\r\n", ilen );
    else
	snprintf(p, blen - (p - bp), "\r\n");

    ctxt->outptr = ctxt->out = bp;
    ctxt->state = XML_NANO_HTTP_WRITE;
    blen = strlen( ctxt->out );
    xmlNanoHTTPSend(ctxt, ctxt->out, blen );

    if ( input != NULL ) {
	xmlNanoHTTPSend( ctxt, input, ilen );
    }

    ctxt->state = XML_NANO_HTTP_READ;

    while ((p = xmlNanoHTTPReadLine(ctxt)) != NULL) {
        if (*p == 0) {
	    ctxt->content = ctxt->inrptr;
	    xmlFree(p);
	    break;
	}
	xmlNanoHTTPScanAnswer(ctxt, p);

        xmlFree(p);
    }

    if ((ctxt->location != NULL) && (ctxt->returnValue >= 300) &&
        (ctxt->returnValue < 400)) {
	while ( xmlNanoHTTPRecv(ctxt) > 0 )
            ;
        if (nbRedirects < XML_NANO_HTTP_MAX_REDIR) {
	    nbRedirects++;
	    if (redirURL != NULL)
		xmlFree(redirURL);
	    redirURL = xmlMemStrdup(ctxt->location);
	    xmlNanoHTTPFreeCtxt(ctxt);
	    goto retry;
	}
	xmlNanoHTTPFreeCtxt(ctxt);
	if (redirURL != NULL) xmlFree(redirURL);
	return(NULL);
    }

    if (contentType != NULL) {
	if (ctxt->contentType != NULL)
	    *contentType = xmlMemStrdup(ctxt->contentType);
	else
	    *contentType = NULL;
    }

    if ((redir != NULL) && (redirURL != NULL)) {
	*redir = redirURL;
    } else {
	if (redirURL != NULL)
	    xmlFree(redirURL);
	if (redir != NULL)
	    *redir = NULL;
    }

    return((void *) ctxt);
}

/**
 * xmlNanoHTTPMethod:
 * @URL:  The URL to load
 * @method:  the HTTP method to use
 * @input:  the input string if any
 * @contentType:  the Content-Type information IN and OUT
 * @headers:  the extra headers
 * @ilen:  input length
 *
 * This function try to open a connection to the indicated resource
 * via HTTP using the given @method, adding the given extra headers
 * and the input buffer for the request content.
 *
 * Returns NULL in case of failure, otherwise a request handler.
 *     The contentType, if provided must be freed by the caller
 */

void*
xmlNanoHTTPMethod(const char *URL, const char *method, const char *input,
                  char **contentType, const char *headers, int ilen) {
    return(xmlNanoHTTPMethodRedir(URL, method, input, contentType,
		                  NULL, headers, ilen));
}

/**
 * xmlNanoHTTPFetch:
 * @URL:  The URL to load
 * @filename:  the filename where the content should be saved
 * @contentType:  if available the Content-Type information will be
 *                returned at that location
 *
 * This function try to fetch the indicated resource via HTTP GET
 * and save it's content in the file.
 *
 * Returns -1 in case of failure, 0 in case of success. The contentType,
 *     if provided must be freed by the caller
 */
int
xmlNanoHTTPFetch(const char *URL, const char *filename, char **contentType) {
    void *ctxt = NULL;
    char *buf = NULL;
    int fd;
    int len;
    int ret = 0;

    if (filename == NULL) return(-1);
    ctxt = xmlNanoHTTPOpen(URL, contentType);
    if (ctxt == NULL) return(-1);

    if (!strcmp(filename, "-"))
        fd = 0;
    else {
        fd = open(filename, O_CREAT | O_WRONLY, 00644);
	if (fd < 0) {
	    xmlNanoHTTPClose(ctxt);
	    if ((contentType != NULL) && (*contentType != NULL)) {
	        xmlFree(*contentType);
		*contentType = NULL;
	    }
	    return(-1);
	}
    }

    xmlNanoHTTPFetchContent( ctxt, &buf, &len );
    if ( len > 0 ) {
	if (write(fd, buf, len) == -1) {
	    ret = -1;
	}
    }

    xmlNanoHTTPClose(ctxt);
    close(fd);
    return(ret);
}

#ifdef LIBXML_OUTPUT_ENABLED
/**
 * xmlNanoHTTPSave:
 * @ctxt:  the HTTP context
 * @filename:  the filename where the content should be saved
 *
 * This function saves the output of the HTTP transaction to a file
 * It closes and free the context at the end
 *
 * Returns -1 in case of failure, 0 in case of success.
 */
int
xmlNanoHTTPSave(void *ctxt, const char *filename) {
    char *buf = NULL;
    int fd;
    int len;
    int ret = 0;

    if ((ctxt == NULL) || (filename == NULL)) return(-1);

    if (!strcmp(filename, "-"))
        fd = 0;
    else {
        fd = open(filename, O_CREAT | O_WRONLY, 0666);
	if (fd < 0) {
	    xmlNanoHTTPClose(ctxt);
	    return(-1);
	}
    }

    xmlNanoHTTPFetchContent( ctxt, &buf, &len );
    if ( len > 0 ) {
	if (write(fd, buf, len) == -1) {
	    ret = -1;
	}
    }

    xmlNanoHTTPClose(ctxt);
    close(fd);
    return(ret);
}
#endif /* LIBXML_OUTPUT_ENABLED */

/**
 * xmlNanoHTTPReturnCode:
 * @ctx:  the HTTP context
 *
 * Get the latest HTTP return code received
 *
 * Returns the HTTP return code for the request.
 */
int
xmlNanoHTTPReturnCode(void *ctx) {
    xmlNanoHTTPCtxtPtr ctxt = (xmlNanoHTTPCtxtPtr) ctx;

    if (ctxt == NULL) return(-1);

    return(ctxt->returnValue);
}

/**
 * xmlNanoHTTPAuthHeader:
 * @ctx:  the HTTP context
 *
 * Get the authentication header of an HTTP context
 *
 * Returns the stashed value of the WWW-Authenticate or Proxy-Authenticate
 * header.
 */
const char *
xmlNanoHTTPAuthHeader(void *ctx) {
    xmlNanoHTTPCtxtPtr ctxt = (xmlNanoHTTPCtxtPtr) ctx;

    if (ctxt == NULL) return(NULL);

    return(ctxt->authHeader);
}

/**
 * xmlNanoHTTPContentLength:
 * @ctx:  the HTTP context
 *
 * Provides the specified content length from the HTTP header.
 *
 * Return the specified content length from the HTTP header.  Note that
 * a value of -1 indicates that the content length element was not included in
 * the response header.
 */
int
xmlNanoHTTPContentLength( void * ctx ) {
    xmlNanoHTTPCtxtPtr	ctxt = (xmlNanoHTTPCtxtPtr)ctx;

    return ( ( ctxt == NULL ) ? -1 : ctxt->ContentLength );
}

/**
 * xmlNanoHTTPRedir:
 * @ctx:  the HTTP context
 *
 * Provides the specified redirection URL if available from the HTTP header.
 *
 * Return the specified redirection URL or NULL if not redirected.
 */
const char *
xmlNanoHTTPRedir( void * ctx ) {
    xmlNanoHTTPCtxtPtr	ctxt = (xmlNanoHTTPCtxtPtr)ctx;

    return ( ( ctxt == NULL ) ? NULL : ctxt->location );
}

/**
 * xmlNanoHTTPEncoding:
 * @ctx:  the HTTP context
 *
 * Provides the specified encoding if specified in the HTTP headers.
 *
 * Return the specified encoding or NULL if not available
 */
const char *
xmlNanoHTTPEncoding( void * ctx ) {
    xmlNanoHTTPCtxtPtr	ctxt = (xmlNanoHTTPCtxtPtr)ctx;

    return ( ( ctxt == NULL ) ? NULL : ctxt->encoding );
}

/**
 * xmlNanoHTTPMimeType:
 * @ctx:  the HTTP context
 *
 * Provides the specified Mime-Type if specified in the HTTP headers.
 *
 * Return the specified Mime-Type or NULL if not available
 */
const char *
xmlNanoHTTPMimeType( void * ctx ) {
    xmlNanoHTTPCtxtPtr	ctxt = (xmlNanoHTTPCtxtPtr)ctx;

    return ( ( ctxt == NULL ) ? NULL : ctxt->mimeType );
}

/**
 * xmlNanoHTTPFetchContent:
 * @ctx:  the HTTP context
 * @ptr:  pointer to set to the content buffer.
 * @len:  integer pointer to hold the length of the content
 *
 * Check if all the content was read
 *
 * Returns 0 if all the content was read and available, returns
 * -1 if received content length was less than specified or an error
 * occurred.
 */
static int
xmlNanoHTTPFetchContent( void * ctx, char ** ptr, int * len ) {
    xmlNanoHTTPCtxtPtr	ctxt = (xmlNanoHTTPCtxtPtr)ctx;

    int			rc = 0;
    int			cur_lgth;
    int			rcvd_lgth;
    int			dummy_int;
    char *		dummy_ptr = NULL;

    /*  Dummy up return input parameters if not provided  */

    if ( len == NULL )
        len = &dummy_int;

    if ( ptr == NULL )
        ptr = &dummy_ptr;

    /*  But can't work without the context pointer  */

    if ( ( ctxt == NULL ) || ( ctxt->content == NULL ) ) {
        *len = 0;
	*ptr = NULL;
	return ( -1 );
    }

    rcvd_lgth = ctxt->inptr - ctxt->content;

    while ( (cur_lgth = xmlNanoHTTPRecv( ctxt )) > 0 ) {

	rcvd_lgth += cur_lgth;
	if ( (ctxt->ContentLength > 0) && (rcvd_lgth >= ctxt->ContentLength) )
	    break;
    }

    *ptr = ctxt->content;
    *len = rcvd_lgth;

    if ( ( ctxt->ContentLength > 0 ) && ( rcvd_lgth < ctxt->ContentLength ) )
        rc = -1;
    else if ( rcvd_lgth == 0 )
	rc = -1;

    return ( rc );
}

#endif /* LIBXML_HTTP_ENABLED */