http_client: register Host and Content-Length headers dynamically

Signed-off-by: Eduardo Silva <[email protected]>

Author: edsiper

src/flb_http_client.c

@@ -441,17 +441,12 @@ struct flb_http_client *flb_http_client(struct flb_upstream_conn *u_conn,
     char *buf = NULL;
     char *str_method = NULL;
     char *fmt_plain =                           \
-        "%s %s HTTP/1.%i\r\n"
-        "Host: %s:%i\r\n"
-        "Content-Length: %i\r\n";
+        "%s %s HTTP/1.%i\r\n";
     char *fmt_proxy =                           \
         "%s http://%s:%i/%s HTTP/1.%i\r\n"
-        "Host: %s:%i\r\n"
-        "Proxy-Connection: KeepAlive\r\n"
-        "Content-Length: %i\r\n";
+        "Proxy-Connection: KeepAlive\r\n";
 
     struct flb_http_client *c;
-    struct flb_upstream *u = u_conn->u;
 
     switch (method) {
     case FLB_HTTP_GET:
@@ -481,8 +476,6 @@ struct flb_http_client *flb_http_client(struct flb_upstream_conn *u_conn,
                        str_method,
                        uri,
                        flags & FLB_HTTP_10 ? 0 : 1,
-                       u->tcp_host,
-                       u->tcp_port,
                        body_len);
     }
     else {
@@ -493,8 +486,6 @@ struct flb_http_client *flb_http_client(struct flb_upstream_conn *u_conn,
                        host,
                        port,
                        "",
-                       host,
-                       port,
                        body_len);
     }
 
@@ -754,13 +745,92 @@ static int http_header_push(struct flb_http_client *c, struct flb_kv *header)
     return 0;
 }
 
+static int header_exists(struct flb_http_client *c, char *header_buf, int len)
+{
+    int found = FLB_FALSE;
+    struct mk_list *head;
+    struct flb_kv *header;
+
+    mk_list_foreach(head, &c->headers) {
+        header = mk_list_entry(head, struct flb_kv, _head);
+        if (flb_sds_len(header->key) != len) {
+            continue;
+        }
+
+        if (strncasecmp(header->key, header_buf, len) == 0) {
+            found = FLB_TRUE;
+            break;
+        }
+    }
+
+    return found;
+}
 
 static int http_headers_compose(struct flb_http_client *c)
 {
     int ret;
+    int len;
+    flb_sds_t tmp;
+    flb_sds_t host;
+    char *out_host;
+    int out_port;
     struct mk_list *head;
     struct flb_kv *header;
+    struct flb_upstream *u = c->u_conn->u;
+
+    /* Check if the 'Host' header exists, if is missing, just add it */
+    ret = header_exists(c, "Host", 4);
+    if (ret == FLB_FALSE) {
+        if (!c->host) {
+            out_host = u->tcp_host;
+        }
+        else {
+            out_host = (char *) c->host;
+        }
+
+        len = strlen(out_host);
+        host = flb_sds_create_size(len + 32);
+        if (!host) {
+            flb_error("[http_client] cannot create temporal buffer");
+            return -1;
+        }
+
+        if (c->port == 0) {
+            out_port = u->tcp_port;
+        }
+        else {
+            out_port = c->port;
+        }
+
+        tmp = flb_sds_printf(&host, "%s:%i", out_host, out_port);
+        if (!tmp) {
+            flb_sds_destroy(host);
+            flb_error("[http_client] cannot compose temporal host header");
+            return -1;
+        }
+
+        flb_http_add_header(c,
+                            "Host", 4,
+                            host, flb_sds_len(host));
+        flb_sds_destroy(host);
+    }
+
+    /* Content-Length */
+    ret = header_exists(c, "Content-Length", 14);
+    if (ret == FLB_FALSE) {
+        if (c->body_len >= 0) {
+            tmp = flb_malloc(32);
+            if (!tmp) {
+                flb_errno();
+                return -1;
+        }
+            len = snprintf(tmp, sizeof(tmp) - 1, "%i", c->body_len);
+            flb_http_add_header(c, "Content-Length", 14, tmp, len);
+            flb_free(tmp);
+        }
+    }
 
+    /* Push header list to one buffer */
     mk_list_foreach(head, &c->headers) {
         header = mk_list_entry(head, struct flb_kv, _head);
         ret = http_header_push(c, header);