Added support for HEAD methods.

Mastodon uses them when it founds an attachment.

activitypub.c

@@ -880,7 +880,7 @@ int activitypub_get_handler(d_char *req, char *q_path,
     xs *msg = NULL;
 
     if (accept == NULL)
-        return 400;
+        return 0;
 
     if (xs_str_in(accept, "application/activity+json") == -1 &&
         xs_str_in(accept, "application/ld+json") == -1)

httpd.c

@@ -7,6 +7,7 @@
 #include "xs_json.h"
 #include "xs_socket.h"
 #include "xs_httpd.h"
+#include "xs_mime.h"
 
 #include "snac.h"
 
@@ -30,7 +31,7 @@ int server_get_handler(d_char *req, char *q_path,
     char *acpt = xs_dict_get(req, "accept");
 
     if (acpt == NULL)
-        return 400;
+        return 0;
 
     /* is it the server root? */
     if (*q_path == '\0') {
@@ -126,7 +127,7 @@ void httpd_connection(FILE *f)
     if (xs_startswith(q_path, p))
         q_path = xs_crop(q_path, strlen(p), 0);
 
-    if (strcmp(method, "GET") == 0) {
+    if (strcmp(method, "GET") == 0 || strcmp(method, "HEAD") == 0) {
         /* cascade through */
         if (status == 0)
             status = server_get_handler(req, q_path, &body, &b_size, &ctype);
@@ -181,6 +182,12 @@ void httpd_connection(FILE *f)
     if (b_size == 0 && body != NULL)
         b_size = strlen(body);
 
+    /* if it was a HEAD, no body will be sent */
+    if (strcmp(method, "HEAD") == 0) {
+        free(body);
+        body = NULL;
+    }
+
     xs_httpd_response(f, status, headers, body, b_size);
 
     fclose(f);