tool_getparam: replace (in-place) '%20' by '+' according to RFC1866

Signed-off-by: Victor Vieux <victorvieux@gmail.com>

Closes #6895

docs/KNOWN_BUGS

@@ -48,7 +48,6 @@ problems may have been fixed or changed somewhat since this was written!
  4.1 -J and -O with %-encoded file names
  4.2 -J with -C - fails
  4.3 --retry and transfer timeouts
- 4.4 Improve --data-urlencode space encoding
 
  5. Build and portability issues
  5.1 OS400 port requires deprecated IBM library
@@ -411,13 +410,6 @@ problems may have been fixed or changed somewhat since this was written!
  https://curl.se/mail/lib-2008-01/0080.html and Mandriva bug report
  https://qa.mandriva.com/show_bug.cgi?id=22565
 
-4.4 Improve --data-urlencode space encoding
-
- ASCII space characters in --data-urlencode are currently encoded as %20
- rather than +, which RFC 1866 says should be used.
-
- See https://github.com/curl/curl/issues/3229
-
 5. Build and portability issues
 
 5.1 OS400 port requires deprecated IBM library

src/tool_getparam.c

@@ -442,6 +442,34 @@ done:
   *certname_place = '\0';
 }
 
+/* Replace (in-place) '%20' by '+' according to RFC1866 */
+static size_t replace_url_encoded_space_by_plus(char *url)
+{
+  size_t orig_len = strlen(url);
+  size_t orig_index = 0;
+  size_t new_index = 0;
+
+  while(orig_index < orig_len) {
+    if((url[orig_index] == '%') &&
+       (url[orig_index + 1] == '2') &&
+       (url[orig_index + 2] == '0')) {
+      url[new_index] = '+';
+      orig_index += 3;
+    }
+    else{
+      if(new_index != orig_index) {
+        url[new_index] = url[orig_index];
+      }
+      orig_index++;
+    }
+    new_index++;
+  }
+
+  url[new_index] = 0; /* terminate string */
+
+  return new_index; /* new size */
+}
+
 static void
 GetFileAndPassword(char *nextarg, char **file, char **password)
 {
@@ -1422,9 +1450,11 @@ ParameterError getparameter(const char *flag, /* f or -long-flag */
           char *enc = curl_easy_escape(NULL, postdata, (int)size);
           Curl_safefree(postdata); /* no matter if it worked or not */
           if(enc) {
+            /* replace (in-place) '%20' by '+' acording to RFC1866 */
+            size_t enclen = replace_url_encoded_space_by_plus(enc);
             /* now make a string with the name from above and append the
                encoded string */
-            size_t outlen = nlen + strlen(enc) + 2;
+            size_t outlen = nlen + enclen + 2;
             char *n = malloc(outlen);
             if(!n) {
               curl_free(enc);

tests/data/test1015

@@ -43,10 +43,10 @@ POST /%TESTNUMBER HTTP/1.1
 Host: %HOSTIP:%HTTPPORT
 User-Agent: curl/%VERSION
 Accept: */*
-Content-Length: 133
+Content-Length: 119
 Content-Type: application/x-www-form-urlencoded
 
-my%20name%20is%20moo%5B%5D&y e s=s_i_r&v_alue=content%20to%20_%3F%21%23%24%27%7C%3C%3E%0A&content%20to%20_%3F%21%23%24%27%7C%3C%3E%0A
+my+name+is+moo%5B%5D&y e s=s_i_r&v_alue=content+to+_%3F%21%23%24%27%7C%3C%3E%0A&content+to+_%3F%21%23%24%27%7C%3C%3E%0A
 </protocol>
 </verify>
 </testcase>