retry on network failure during url fetch

[ppastats.git] / src / lp_ws.c

diff --git a/src/lp_ws.c b/src/lp_ws.c
index 4b51be8..b6957eb 100644 (file)
--- a/src/lp_ws.c
+++ b/src/lp_ws.c
@@ -19,6 +19,7 @@
 
 #include <stdlib.h>
 #include <string.h>
+#include <unistd.h>
 
 #include <curl/curl.h>
 #include <json/json.h>
@@ -35,6 +36,8 @@
 #define QUERY_GET_DAILY_DOWNLOAD_TOTALS \
        "?ws.op=getDailyDownloadTotals"
 
+static int DEFAULT_FETCH_RETRIES = 3;
+
 static CURL *curl;
 
 struct ucontent {
@@ -59,13 +62,16 @@ static size_t cbk_curl(void *buffer, size_t size, size_t nmemb, void *userp)
 static char *fetch_url(const char *url)
 {
        struct ucontent *content = malloc(sizeof(struct ucontent));
-       char *result = NULL;
+       char *result;
        long code;
+       int retries;
 
        if (debug)
                printf("DEBUG: fetch_url %s\n", url);
 
        if (!curl) {
+               if (debug)
+                       printf("DEBUG: initializing CURL\n");
                curl_global_init(CURL_GLOBAL_ALL);
                curl = curl_easy_init();
        }
@@ -73,6 +79,11 @@ static char *fetch_url(const char *url)
        if (!curl)
                exit(EXIT_FAILURE);
 
+       result = NULL;
+
+       retries = DEFAULT_FETCH_RETRIES;
+
+ retrieve:
        content->data = malloc(1);
        content->data[0] = '\0';
        content->len = 0;
@@ -84,10 +95,30 @@ static char *fetch_url(const char *url)
        curl_easy_setopt(curl, CURLOPT_USERAGENT, "ppastats/0.0");
 
        if (curl_easy_perform(curl) == CURLE_OK) {
-
                curl_easy_getinfo(curl, CURLINFO_RESPONSE_CODE, &code);
-               if (code == 200)
+
+               switch (code) {
+               case 200:
                        result = content->data;
+                       break;
+               case 500:
+               case 502:
+               case 503:
+               case 504:
+                       if (retries) {
+                               fprintf(stderr, "Fetch failed: %ld\n", code);
+
+                               if (debug)
+                                       printf("Wait 5s before retry.\n");
+                               sleep(5);
+
+                               free(content->data);
+                               retries--;
+                               goto retrieve;
+                       }
+               default:
+                       fprintf(stderr, "Fetch failed: %ld\n", code);
+               }
        }
 
        if (!result)