net: get gateway url

basic api http_get function, (which the definition of will def. change
in the future)

uses libcurl to get the api /gateway to get the wss url, and assumes a
url in case of failure so we at least try authenticating

2 files changed, 91 insertions, 3 deletions

diff --git a/net/api.c b/net/api.c
new file mode 100644
index 0000000..e664c42
--- /dev/null
+++ b/net/api.c
@@ -0,0 +1,43 @@
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <curl/curl.h>
+
+extern char *token;
+
+int http_get(char *url)
+{
+    int pipefd[2];
+    if(pipe(pipefd) < 0)
+        return -errno;
+
+    FILE *write_end = fdopen(pipefd[1], "w");
+
+    int ret = pipefd[0];
+
+    CURL *job = curl_easy_init();
+    if(job == 0) {
+        close(pipefd[0]);
+        ret = -1;
+        goto close_writepipe;
+    }
+
+    curl_easy_setopt(job, CURLOPT_URL, url);
+    curl_easy_setopt(job, CURLOPT_WRITEDATA, write_end);
+    curl_easy_setopt(job, CURLOPT_HTTPHEADER, curl_slist_append(NULL, token));
+    CURLcode res = curl_easy_perform(job);
+
+    if(res > 0) {
+        ret = -res;
+        close(pipefd[0]);
+        goto cleanup;
+    }
+
+cleanup:
+    curl_easy_cleanup(job);
+close_writepipe:
+    fclose(write_end);
+    return ret;
+}
diff --git a/net/net.c b/net/net.c
index 4288ae4..9ed4653 100644
--- a/net/net.c
+++ b/net/net.c
@@ -1,18 +1,63 @@
+#include <stdlib.h>
+#include <string.h>
 #include <unistd.h>
 
+#include <cJSON.h>
+#include <curl/curl.h>
+
 #include <init.h>
 #include <log.h>
 #include <subsys.h>
 
+extern int http_get(char *url);
+char *gateway_url;
+
 int net_subsystem(void)
 {
-    print(LOG_NOTICE "net: starting net subsystem");
-    usleep(10000); // do net stuff
+    print(LOG_INFO "net: starting net subsystem");
+
+
     return 0;
 }
 
+void net_get_gateway_url()
+{
+    int fd = http_get("https://discord.com/api/gateway/bot");
+    if(fd < 0) {
+        print(LOG_ERR "net: failed to get gateway url (error %d)", -fd);
+        goto assume;
+    }
+
+    char buf[512];
+    int buf_length = read(fd, buf, 512);
+    close(fd);
+
+    cJSON *gateway_info = cJSON_ParseWithLength(buf, buf_length);
+    cJSON *gateway_url_json = cJSON_GetObjectItemCaseSensitive(gateway_info, "url");
+    if(!cJSON_IsString(gateway_url_json) || gateway_url_json->valuestring == NULL) {
+        print(LOG_ERR "net: cannot get gateway url from api (token invalid?)");
+        cJSON_Delete(gateway_info);
+        goto assume;
+    }
+
+    char *gateway_url = calloc(strlen(gateway_url_json->valuestring) + 1, sizeof(char));
+    strcpy(gateway_url, gateway_url_json->valuestring);
+    print(LOG_DEBUG "net: using gateway url %s", gateway_url);
+
+    free(gateway_url);
+    cJSON_Delete(gateway_info);
+    return;
+
+assume:
+    print(LOG_DEBUG "net: assuming gateway url wss://gateway.discord.gg");
+    gateway_url = calloc(strlen("wss://gateway.discord.gg") + 1, sizeof(char));
+    strcpy(gateway_url, "wss://gateway.discord.gg");
+    return;
+}
+l1_initcall(net_get_gateway_url);
+
 void net_initcall()
 {
     start_subsystem(net_subsystem);
 }
-l1_initcall(net_initcall);
+l2_initcall(net_initcall);