src/http.c

   1 /*
   2  * Copyright (C) 2011-2015 jeanfi@gmail.com
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License as
   6  * published by the Free Software Foundation; either version 2 of the
   7  * License, or (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  17  * 02110-1301 USA
  18  */
  19
  20 #include <libintl.h>
  21 #define _(String) gettext(String)
  22
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <unistd.h>
  26
  27 #include <curl/curl.h>
  28
  29 #include "fcache.h"
  30 #include "http.h"
  31 #include <plog.h>
  32
  33 static const int DEFAULT_FETCH_RETRIES = 10;
  34
  35 static CURL *curl;
  36
  37 struct ucontent {
  38         char *data;
  39         size_t len;
  40 };
  41
  42 static size_t cbk_curl(void *buffer, size_t size, size_t nmemb, void *userp)
  43 {
  44         size_t realsize = size * nmemb;
  45         struct ucontent *mem = (struct ucontent *)userp;
  46
  47         mem->data = realloc(mem->data, mem->len + realsize + 1);
  48
  49         memcpy(&(mem->data[mem->len]), buffer, realsize);
  50         mem->len += realsize;
  51         mem->data[mem->len] = 0;
  52
  53         return realsize;
  54 }
  55
  56 static void init()
  57 {
  58         if (!curl) {
  59                 log_debug(_("initializing CURL"));
  60                 curl_global_init(CURL_GLOBAL_ALL);
  61                 curl = curl_easy_init();
  62         }
  63
  64         if (!curl)
  65                 exit(EXIT_FAILURE);
  66 }
  67
  68 static char *fetch_url(const char *url)
  69 {
  70         struct ucontent *content = malloc(sizeof(struct ucontent));
  71         char *result;
  72         long code;
  73         int retries;
  74         unsigned int s;
  75
  76         log_debug(_("fetch_url(): %s"), url);
  77
  78         init();
  79
  80         result = NULL;
  81
  82         retries = DEFAULT_FETCH_RETRIES;
  83
  84  retrieve:
  85         content->data = malloc(1);
  86         content->data[0] = '\0';
  87         content->len = 0;
  88
  89         curl_easy_setopt(curl, CURLOPT_URL, url);
  90         curl_easy_setopt(curl, CURLOPT_VERBOSE, 0);
  91         curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, cbk_curl);
  92         curl_easy_setopt(curl, CURLOPT_WRITEDATA, content);
  93         curl_easy_setopt(curl, CURLOPT_USERAGENT, "ppastats/0.0");
  94 #ifdef CURLOPT_TRANSFER_ENCODING
  95         /* added since Curl 7.21.7 */
  96         curl_easy_setopt(curl, CURLOPT_TRANSFER_ENCODING, 1);
  97 #endif
  98
  99         if (curl_easy_perform(curl) == CURLE_OK) {
 100                 curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &code);
 101
 102                 switch (code) {
 103                 case 200:
 104                         result = content->data;
 105                         break;
 106                 case 500:
 107                 case 502:
 108                 case 503:
 109                 case 504:
 110                         log_err(_("Fetch failed with code %ld for URL %s"),
 111                                 code,
 112                                 url);
 113
 114                         if (retries) {
 115                                 s = 2 * (DEFAULT_FETCH_RETRIES - retries) + 2;
 116                                 log_debug(_("Wait %ds before retry"), s);
 117                                 sleep(s);
 118
 119                                 free(content->data);
 120                                 retries--;
 121                                 goto retrieve;
 122                         }
 123
 124                         break;
 125                 default:
 126                         log_err(_("Fetch failed with code %ld for URL %s"),
 127                                 code,
 128                                 url);
 129                 }
 130         }
 131
 132         if (!result)
 133                 free(content->data);
 134
 135         free(content);
 136
 137         return result;
 138 }
 139
 140 void http_cleanup()
 141 {
 142         log_fct_enter();
 143
 144         curl_easy_cleanup(curl);
 145         curl_global_cleanup();
 146
 147         log_fct_exit();
 148 }
 149
 150 char *get_url_content(const char *url, unsigned int use_cache)
 151 {
 152         char *content;
 153
 154         content = NULL;
 155
 156         if (use_cache)
 157                 content = fcache_get(url + 7);
 158
 159         if (!content)
 160                 content = fetch_url(url);
 161
 162         if (use_cache && content)
 163                 fcache_put(url + 7, content);
 164
 165         return content;
 166 }