/*
  * HTTP protocol for ffmpeg client

  * Copyright (c) 2000, 2001 Fabrice Bellard

  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */

 
 #include "libavutil/avstring.h"

 #include "avformat.h"
 #include <unistd.h>

 #include "internal.h"

 #include "network.h"

 #include "http.h"

 #include "os_support.h"

 #include "httpauth.h"

 #include "url.h"

 #include "libavutil/opt.h"

 /* XXX: POST protocol is not completely implemented because ffmpeg uses
    only a subset of it. */

 
 /* used for protocol handling */
 #define BUFFER_SIZE 1024
 #define MAX_REDIRECTS 8
 
 typedef struct {

     const AVClass *class;

     URLContext *hd;
     unsigned char buffer[BUFFER_SIZE], *buf_ptr, *buf_end;
     int line_count;
     int http_code;

     int64_t chunksize;      /**< Used if "Transfer-Encoding: chunked" otherwise -1. */

     char *user_agent;

     int64_t off, filesize;

     char location[MAX_URL_SIZE];

     HTTPAuthState auth_state;

     HTTPAuthState proxy_auth_state;

     char *headers;

     int willclose;          /**< Set if the server correctly handles Connection: close and will close the connection after feeding us the content. */

     int chunked_post;

 } HTTPContext;
 

 #define OFFSET(x) offsetof(HTTPContext, x)

 #define D AV_OPT_FLAG_DECODING_PARAM
 #define E AV_OPT_FLAG_ENCODING_PARAM

 #define DEC AV_OPT_FLAG_DECODING_PARAM

 static const AVOption options[] = {

 {"chunked_post", "use chunked transfer-encoding for posts", OFFSET(chunked_post), AV_OPT_TYPE_INT, {.dbl = 1}, 0, 1, E },

 {"headers", "custom HTTP headers, can override built in default headers", OFFSET(headers), AV_OPT_TYPE_STRING, { 0 }, 0, 0, D|E },

 {"user-agent", "override User-Agent header", OFFSET(user_agent), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, DEC},

 {NULL}
 };

 #define HTTP_CLASS(flavor)\
 static const AVClass flavor ## _context_class = {\
     .class_name     = #flavor,\
     .item_name      = av_default_item_name,\
     .option         = options,\
     .version        = LIBAVUTIL_VERSION_INT,\

 };
 

 HTTP_CLASS(http);
 HTTP_CLASS(https);
 

 static int http_connect(URLContext *h, const char *path, const char *local_path,
                         const char *hoststr, const char *auth,
                         const char *proxyauth, int *new_location);

 void ff_http_init_auth_state(URLContext *dest, const URLContext *src)
 {
     memcpy(&((HTTPContext*)dest->priv_data)->auth_state,
            &((HTTPContext*)src->priv_data)->auth_state, sizeof(HTTPAuthState));

     memcpy(&((HTTPContext*)dest->priv_data)->proxy_auth_state,
            &((HTTPContext*)src->priv_data)->proxy_auth_state,
            sizeof(HTTPAuthState));

 }
 

 /* return non zero if error */
 static int http_open_cnx(URLContext *h)
 {

     const char *path, *proxy_path, *lower_proto = "tcp", *local_path;

     char hostname[1024], hoststr[1024], proto[10];

     char auth[1024], proxyauth[1024] = "";

     char path1[1024];

     char buf[1024], urlbuf[1024];

     int port, use_proxy, err, location_changed = 0, redirects = 0;

     HTTPAuthType cur_auth_type, cur_proxy_auth_type;

     HTTPContext *s = h->priv_data;
     URLContext *hd = NULL;
 
     proxy_path = getenv("http_proxy");
     use_proxy = (proxy_path != NULL) && !getenv("no_proxy") &&

         av_strstart(proxy_path, "http://", NULL);

 
     /* fill the dest addr */
  redo:
     /* needed in any case to build the host string */

     av_url_split(proto, sizeof(proto), auth, sizeof(auth),
                  hostname, sizeof(hostname), &port,

                  path1, sizeof(path1), s->location);

     ff_url_join(hoststr, sizeof(hoststr), NULL, NULL, hostname, port, NULL);

     if (!strcmp(proto, "https")) {
         lower_proto = "tls";

         use_proxy = 0;

         if (port < 0)
             port = 443;
     }
     if (port < 0)
         port = 80;
 

     if (path1[0] == '\0')
         path = "/";
     else
         path = path1;
     local_path = path;

     if (use_proxy) {

         /* Reassemble the request URL without auth string - we don't
          * want to leak the auth to the proxy. */
         ff_url_join(urlbuf, sizeof(urlbuf), proto, NULL, hostname, port, "%s",
                     path1);
         path = urlbuf;
         av_url_split(NULL, 0, proxyauth, sizeof(proxyauth),
                      hostname, sizeof(hostname), &port, NULL, 0, proxy_path);

     }
 

     ff_url_join(buf, sizeof(buf), lower_proto, NULL, hostname, port, NULL);

     err = ffurl_open(&hd, buf, AVIO_FLAG_READ_WRITE,
                      &h->interrupt_callback, NULL);

     if (err < 0)
         goto fail;
 
     s->hd = hd;

     cur_auth_type = s->auth_state.auth_type;

     cur_proxy_auth_type = s->auth_state.auth_type;
     if (http_connect(h, path, local_path, hoststr, auth, proxyauth, &location_changed) < 0)

         goto fail;

     if (s->http_code == 401) {
         if (cur_auth_type == HTTP_AUTH_NONE && s->auth_state.auth_type != HTTP_AUTH_NONE) {

             ffurl_close(hd);

             goto redo;
         } else
             goto fail;
     }

     if (s->http_code == 407) {
         if (cur_proxy_auth_type == HTTP_AUTH_NONE &&
             s->proxy_auth_state.auth_type != HTTP_AUTH_NONE) {
             ffurl_close(hd);
             goto redo;
         } else
             goto fail;
     }

     if ((s->http_code == 301 || s->http_code == 302 || s->http_code == 303 || s->http_code == 307)
         && location_changed == 1) {

         /* url moved, get next */

         ffurl_close(hd);

         if (redirects++ >= MAX_REDIRECTS)

             return AVERROR(EIO);

         location_changed = 0;
         goto redo;
     }
     return 0;
  fail:
     if (hd)

         ffurl_close(hd);

     s->hd = NULL;

     return AVERROR(EIO);

 }
 
 static int http_open(URLContext *h, const char *uri, int flags)
 {

     HTTPContext *s = h->priv_data;

 
     h->is_streamed = 1;
 
     s->filesize = -1;

     av_strlcpy(s->location, uri, sizeof(s->location));

     if (s->headers) {
         int len = strlen(s->headers);
         if (len < 2 || strcmp("\r\n", s->headers + len - 2))

             av_log(h, AV_LOG_WARNING, "No trailing CRLF found in HTTP header.\n");

     }
 

     return http_open_cnx(h);

 }
 static int http_getc(HTTPContext *s)
 {
     int len;
     if (s->buf_ptr >= s->buf_end) {

         len = ffurl_read(s->hd, s->buffer, BUFFER_SIZE);

         if (len < 0) {

             return AVERROR(EIO);

         } else if (len == 0) {
             return -1;
         } else {
             s->buf_ptr = s->buffer;
             s->buf_end = s->buffer + len;
         }
     }
     return *s->buf_ptr++;
 }
 

 static int http_get_line(HTTPContext *s, char *line, int line_size)
 {
     int ch;
     char *q;
 
     q = line;
     for(;;) {
         ch = http_getc(s);
         if (ch < 0)
             return AVERROR(EIO);
         if (ch == '\n') {
             /* process line */
             if (q > line && q[-1] == '\r')
                 q--;
             *q = '\0';
 
             return 0;
         } else {
             if ((q - line) < line_size - 1)
                 *q++ = ch;
         }
     }
 }
 

 static int process_line(URLContext *h, char *line, int line_count,
                         int *new_location)
 {
     HTTPContext *s = h->priv_data;

     char *tag, *p, *end;

 
     /* end of header */
     if (line[0] == '\0')
         return 0;
 
     p = line;
     if (line_count == 0) {
         while (!isspace(*p) && *p != '\0')
             p++;
         while (isspace(*p))
             p++;

         s->http_code = strtol(p, &end, 10);

         av_dlog(NULL, "http_code=%d\n", s->http_code);

         /* error codes are 4xx and 5xx, but regard 401 as a success, so we
          * don't abort until all headers have been parsed. */

         if (s->http_code >= 400 && s->http_code < 600 && (s->http_code != 401

             || s->auth_state.auth_type != HTTP_AUTH_NONE) &&
             (s->http_code != 407 || s->proxy_auth_state.auth_type != HTTP_AUTH_NONE)) {

             end += strspn(end, SPACE_CHARS);

             av_log(h, AV_LOG_WARNING, "HTTP error %d %s\n",

                    s->http_code, end);

             return -1;

         }

     } else {
         while (*p != '\0' && *p != ':')
             p++;
         if (*p != ':')
             return 1;
 
         *p = '\0';
         tag = line;
         p++;
         while (isspace(*p))
             p++;

         if (!av_strcasecmp(tag, "Location")) {

             strcpy(s->location, p);
             *new_location = 1;

         } else if (!av_strcasecmp (tag, "Content-Length") && s->filesize == -1) {

             s->filesize = atoll(p);

         } else if (!av_strcasecmp (tag, "Content-Range")) {

             /* "bytes $from-$to/$document_size" */
             const char *slash;
             if (!strncmp (p, "bytes ", 6)) {
                 p += 6;
                 s->off = atoll(p);
                 if ((slash = strchr(p, '/')) && strlen(slash) > 0)
                     s->filesize = atoll(slash+1);
             }
             h->is_streamed = 0; /* we _can_ in fact seek */

         } else if (!av_strcasecmp(tag, "Accept-Ranges") && !strncmp(p, "bytes", 5)) {

             h->is_streamed = 0;

         } else if (!av_strcasecmp (tag, "Transfer-Encoding") && !av_strncasecmp(p, "chunked", 7)) {

             s->filesize = -1;
             s->chunksize = 0;

         } else if (!av_strcasecmp (tag, "WWW-Authenticate")) {

             ff_http_auth_handle_header(&s->auth_state, tag, p);

         } else if (!av_strcasecmp (tag, "Authentication-Info")) {

             ff_http_auth_handle_header(&s->auth_state, tag, p);

         } else if (!av_strcasecmp (tag, "Proxy-Authenticate")) {
             ff_http_auth_handle_header(&s->proxy_auth_state, tag, p);

         } else if (!av_strcasecmp (tag, "Connection")) {

             if (!strcmp(p, "close"))
                 s->willclose = 1;

         }
     }
     return 1;
 }
 

 static inline int has_header(const char *str, const char *header)
 {
     /* header + 2 to skip over CRLF prefix. (make sure you have one!) */

     if (!str)
         return 0;

     return av_stristart(str, header + 2, NULL) || av_stristr(str, header);
 }
 

 static int http_connect(URLContext *h, const char *path, const char *local_path,
                         const char *hoststr, const char *auth,
                         const char *proxyauth, int *new_location)

 {
     HTTPContext *s = h->priv_data;

     int post, err;
     char line[1024];

     char headers[1024] = "";

     char *authstr = NULL, *proxyauthstr = NULL;

     int64_t off = s->off;

     int len = 0;

     const char *method;

 
 
     /* send http header */

     post = h->flags & AVIO_FLAG_WRITE;

     method = post ? "POST" : "GET";
     authstr = ff_http_auth_create_response(&s->auth_state, auth, local_path,
                                            method);
     proxyauthstr = ff_http_auth_create_response(&s->proxy_auth_state, proxyauth,
                                                 local_path, method);

 
     /* set default headers if needed */
     if (!has_header(s->headers, "\r\nUser-Agent: "))

         len += av_strlcatf(headers + len, sizeof(headers) - len,
                            "User-Agent: %s\r\n",
                            s->user_agent ? s->user_agent : LIBAVFORMAT_IDENT);

     if (!has_header(s->headers, "\r\nAccept: "))
         len += av_strlcpy(headers + len, "Accept: */*\r\n",
                           sizeof(headers) - len);

     if (!has_header(s->headers, "\r\nRange: ") && !post)

         len += av_strlcatf(headers + len, sizeof(headers) - len,

                            "Range: bytes=%"PRId64"-\r\n", s->off);

     if (!has_header(s->headers, "\r\nConnection: "))
         len += av_strlcpy(headers + len, "Connection: close\r\n",
                           sizeof(headers)-len);
     if (!has_header(s->headers, "\r\nHost: "))
         len += av_strlcatf(headers + len, sizeof(headers) - len,
                            "Host: %s\r\n", hoststr);
 
     /* now add in custom headers */

     if (s->headers)
         av_strlcpy(headers + len, s->headers, sizeof(headers) - len);

     snprintf(s->buffer, sizeof(s->buffer),
              "%s %s HTTP/1.1\r\n"

              "%s"

              "%s"

              "%s"

              "%s%s"

              "\r\n",

              method,

              path,

              post && s->chunked_post ? "Transfer-Encoding: chunked\r\n" : "",

              headers,

              authstr ? authstr : "",
              proxyauthstr ? "Proxy-" : "", proxyauthstr ? proxyauthstr : "");

     av_freep(&authstr);

     av_freep(&proxyauthstr);

     if (ffurl_write(s->hd, s->buffer, strlen(s->buffer)) < 0)

         return AVERROR(EIO);

 
     /* init input buffer */
     s->buf_ptr = s->buffer;
     s->buf_end = s->buffer;
     s->line_count = 0;
     s->off = 0;

     s->filesize = -1;

     s->willclose = 0;

     if (post) {

         /* Pretend that it did work. We didn't read any header yet, since
          * we've still to send the POST data, but the code calling this
          * function will check http_code after we return. */
         s->http_code = 200;

         return 0;
     }

     s->chunksize = -1;

 
     /* wait for header */
     for(;;) {

         if (http_get_line(s, line, sizeof(line)) < 0)

             return AVERROR(EIO);

         av_dlog(NULL, "header='%s'\n", line);

         err = process_line(h, line, s->line_count, new_location);
         if (err < 0)
             return err;
         if (err == 0)
             break;
         s->line_count++;

     }
 
     return (off == s->off) ? 0 : -1;
 }
 
 

 static int http_buf_read(URLContext *h, uint8_t *buf, int size)

 {
     HTTPContext *s = h->priv_data;
     int len;

     /* read bytes from input buffer first */
     len = s->buf_end - s->buf_ptr;
     if (len > 0) {
         if (len > size)
             len = size;
         memcpy(buf, s->buf_ptr, len);
         s->buf_ptr += len;
     } else {
         if (!s->willclose && s->filesize >= 0 && s->off >= s->filesize)
             return AVERROR_EOF;
         len = ffurl_read(s->hd, buf, size);
     }
     if (len > 0) {
         s->off += len;
         if (s->chunksize > 0)
             s->chunksize -= len;
     }
     return len;
 }
 
 static int http_read(URLContext *h, uint8_t *buf, int size)
 {
     HTTPContext *s = h->priv_data;

     if (s->chunksize >= 0) {
         if (!s->chunksize) {
             char line[32];
 
             for(;;) {
                 do {
                     if (http_get_line(s, line, sizeof(line)) < 0)
                         return AVERROR(EIO);
                 } while (!*line);    /* skip CR LF from last chunk */
 
                 s->chunksize = strtoll(line, NULL, 16);
 

                 av_dlog(NULL, "Chunked encoding data size: %"PRId64"'\n", s->chunksize);

 
                 if (!s->chunksize)
                     return 0;
                 break;
             }
         }
         size = FFMIN(size, s->chunksize);
     }

     return http_buf_read(h, buf, size);

 }
 
 /* used only when posting data */

 static int http_write(URLContext *h, const uint8_t *buf, int size)

 {

     char temp[11] = "";  /* 32-bit hex + CRLF + nul */

     int ret;
     char crlf[] = "\r\n";

     HTTPContext *s = h->priv_data;

     if (!s->chunked_post) {

         /* non-chunked data is sent without any special encoding */

         return ffurl_write(s->hd, buf, size);

     }
 
     /* silently ignore zero-size data since chunk encoding that would
      * signal EOF */
     if (size > 0) {
         /* upload data using chunked encoding */

         snprintf(temp, sizeof(temp), "%x\r\n", size);

         if ((ret = ffurl_write(s->hd, temp, strlen(temp))) < 0 ||
             (ret = ffurl_write(s->hd, buf, size)) < 0 ||
             (ret = ffurl_write(s->hd, crlf, sizeof(crlf) - 1)) < 0)

             return ret;
     }
     return size;

 }
 
 static int http_close(URLContext *h)
 {

     int ret = 0;
     char footer[] = "0\r\n\r\n";

     HTTPContext *s = h->priv_data;

 
     /* signal end of chunked encoding if used */

     if ((h->flags & AVIO_FLAG_WRITE) && s->chunked_post) {

         ret = ffurl_write(s->hd, footer, sizeof(footer) - 1);

         ret = ret > 0 ? 0 : ret;
     }
 

     if (s->hd)

         ffurl_close(s->hd);

     return ret;

 }
 

 static int64_t http_seek(URLContext *h, int64_t off, int whence)

 {
     HTTPContext *s = h->priv_data;
     URLContext *old_hd = s->hd;

     int64_t old_off = s->off;

     uint8_t old_buf[BUFFER_SIZE];
     int old_buf_size;

 
     if (whence == AVSEEK_SIZE)
         return s->filesize;
     else if ((s->filesize == -1 && whence == SEEK_END) || h->is_streamed)
         return -1;
 
     /* we save the old context in case the seek fails */

     old_buf_size = s->buf_end - s->buf_ptr;
     memcpy(old_buf, s->buf_ptr, old_buf_size);

     s->hd = NULL;
     if (whence == SEEK_CUR)
         off += s->off;
     else if (whence == SEEK_END)
         off += s->filesize;
     s->off = off;
 
     /* if it fails, continue on old connection */
     if (http_open_cnx(h) < 0) {

         memcpy(s->buffer, old_buf, old_buf_size);
         s->buf_ptr = s->buffer;
         s->buf_end = s->buffer + old_buf_size;

         s->hd = old_hd;
         s->off = old_off;
         return -1;
     }

     ffurl_close(old_hd);

     return off;
 }
 

 static int
 http_get_file_handle(URLContext *h)
 {
     HTTPContext *s = h->priv_data;

     return ffurl_get_file_handle(s->hd);

 }
 

 #if CONFIG_HTTP_PROTOCOL

 URLProtocol ff_http_protocol = {

     .name                = "http",
     .url_open            = http_open,
     .url_read            = http_read,
     .url_write           = http_write,
     .url_seek            = http_seek,
     .url_close           = http_close,

     .url_get_file_handle = http_get_file_handle,

     .priv_data_size      = sizeof(HTTPContext),

     .priv_data_class     = &http_context_class,

 };

 #endif
 #if CONFIG_HTTPS_PROTOCOL
 URLProtocol ff_https_protocol = {
     .name                = "https",
     .url_open            = http_open,
     .url_read            = http_read,
     .url_write           = http_write,
     .url_seek            = http_seek,
     .url_close           = http_close,
     .url_get_file_handle = http_get_file_handle,
     .priv_data_size      = sizeof(HTTPContext),

     .priv_data_class     = &https_context_class,

 };
 #endif

 
 #if CONFIG_HTTPPROXY_PROTOCOL
 static int http_proxy_close(URLContext *h)
 {
     HTTPContext *s = h->priv_data;
     if (s->hd)
         ffurl_close(s->hd);
     return 0;
 }
 
 static int http_proxy_open(URLContext *h, const char *uri, int flags)
 {
     HTTPContext *s = h->priv_data;
     char hostname[1024], hoststr[1024];
     char auth[1024], pathbuf[1024], *path;
     char line[1024], lower_url[100];
     int port, ret = 0;
     HTTPAuthType cur_auth_type;
     char *authstr;
 
     h->is_streamed = 1;
 
     av_url_split(NULL, 0, auth, sizeof(auth), hostname, sizeof(hostname), &port,
                  pathbuf, sizeof(pathbuf), uri);
     ff_url_join(hoststr, sizeof(hoststr), NULL, NULL, hostname, port, NULL);
     path = pathbuf;
     if (*path == '/')
         path++;
 
     ff_url_join(lower_url, sizeof(lower_url), "tcp", NULL, hostname, port,
                 NULL);
 redo:
     ret = ffurl_open(&s->hd, lower_url, AVIO_FLAG_READ_WRITE,
                      &h->interrupt_callback, NULL);
     if (ret < 0)
         return ret;
 
     authstr = ff_http_auth_create_response(&s->proxy_auth_state, auth,
                                            path, "CONNECT");
     snprintf(s->buffer, sizeof(s->buffer),
              "CONNECT %s HTTP/1.1\r\n"
              "Host: %s\r\n"
              "Connection: close\r\n"
              "%s%s"
              "\r\n",
              path,
              hoststr,
              authstr ? "Proxy-" : "", authstr ? authstr : "");
     av_freep(&authstr);
 
     if ((ret = ffurl_write(s->hd, s->buffer, strlen(s->buffer))) < 0)
         goto fail;
 
     s->buf_ptr = s->buffer;
     s->buf_end = s->buffer;
     s->line_count = 0;
     s->filesize = -1;
     cur_auth_type = s->proxy_auth_state.auth_type;
 
     for (;;) {
         int new_loc;
         // Note: This uses buffering, potentially reading more than the
         // HTTP header. If tunneling a protocol where the server starts
         // the conversation, we might buffer part of that here, too.
         // Reading that requires using the proper ffurl_read() function
         // on this URLContext, not using the fd directly (as the tls
         // protocol does). This shouldn't be an issue for tls though,
         // since the client starts the conversation there, so there
         // is no extra data that we might buffer up here.
         if (http_get_line(s, line, sizeof(line)) < 0) {
             ret = AVERROR(EIO);
             goto fail;
         }
 
         av_dlog(h, "header='%s'\n", line);
 
         ret = process_line(h, line, s->line_count, &new_loc);
         if (ret < 0)
             goto fail;
         if (ret == 0)
             break;
         s->line_count++;
     }
     if (s->http_code == 407 && cur_auth_type == HTTP_AUTH_NONE &&
         s->proxy_auth_state.auth_type != HTTP_AUTH_NONE) {
         ffurl_close(s->hd);
         s->hd = NULL;
         goto redo;
     }
 
     if (s->http_code < 400)
         return 0;
     ret = AVERROR(EIO);
 
 fail:
     http_proxy_close(h);
     return ret;
 }
 
 static int http_proxy_write(URLContext *h, const uint8_t *buf, int size)
 {
     HTTPContext *s = h->priv_data;
     return ffurl_write(s->hd, buf, size);
 }
 
 URLProtocol ff_httpproxy_protocol = {
     .name                = "httpproxy",
     .url_open            = http_proxy_open,
     .url_read            = http_buf_read,
     .url_write           = http_proxy_write,
     .url_close           = http_proxy_close,
     .url_get_file_handle = http_get_file_handle,
     .priv_data_size      = sizeof(HTTPContext),
 };
 #endif