Add support for sending files in HTTP forms.

include/curl_wrapper.hpp

@@ -297,9 +297,9 @@ private:
     /*!
      *  @brief  Add `*curl_mimepart` to `*curl_mime`.
      *
-     *  @param  mime Initialized `*curl_mime`.
-     *  @param  name Name of the field.
-     *  @param  data Data of the field, or \@filename.
+     *  @param  mime Initialized `*curl_mime`.  @param name Name of the field.
+     *  @param  data Data of the field. If it begins with <tt>`\@file:<tt>, the
+     *               rest of the ergument is treated as a filename.
      *
      *  @since  0.1.1
      */

include/mastodonpp.hpp

@@ -69,7 +69,10 @@
  *
  *  @subsection input Input
  *
- *  All text input is expected to be UTF-8.
+ *  * All text input is expected to be UTF-8.
+ *
+ *  * To send a file, use “<tt>\@file:</tt>” followed by the file name as value
+ *    in the @link mastodonpp::parametermap parametermap@endlink.
  *
  *  @section exceptions Exceptions
  *

src/curl_wrapper.cpp

@@ -354,7 +354,15 @@ void CURLWrapper::add_mime_part(curl_mime *mime,
         throw CURLException{code, "Could not build HTTP form."};
     }
 
-    code = curl_mime_data(part, data.data(), CURL_ZERO_TERMINATED);
+    if (data.substr(0, 6) == "@file:")
+    {
+        const string_view filename{data.substr(6)};
+        code = curl_mime_filedata(part, filename.data());
+    }
+    else
+    {
+        code = curl_mime_data(part, data.data(), CURL_ZERO_TERMINATED);
+    }
     if (code != CURLE_OK)
     {
         throw CURLException{code, "Could not build HTTP form."};