Add example for posting an attachment.

examples/example04_post_with_attachment.cpp

@@ -0,0 +1,99 @@
+/*  This file is part of mastodonpp.
+ *  Copyright © 2020 tastytea <tastytea@tastytea.de>
+ *
+ *  Permission to use, copy, modify, and/or distribute this software for any
+ *  purpose with or without fee is hereby granted.
+ *
+ *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ *  SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ *  OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ *  CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+// Post a status (/api/v1/status) with an attachment (/api/v1/media).
+
+#include "mastodonpp.hpp"
+
+#include <iostream>
+#include <string>
+#include <string_view>
+#include <vector>
+
+namespace masto = mastodonpp;
+using std::cout;
+using std::cerr;
+using std::endl;
+using std::string;
+using std::to_string;
+using std::string_view;
+using std::vector;
+
+int main(int argc, char *argv[])
+{
+    const vector<string_view> args(argv, argv + argc);
+    if (args.size() <= 3)
+    {
+        cerr << "Usage: " << args[0] << " <instance hostname> <access token> <file>\n";
+        return 1;
+    }
+
+    try
+    {
+        // Initialize an Instance and a Connection.
+        masto::Instance instance{args[1], args[2]};
+        masto::Connection connection{instance};
+        const string_view filename{args[3]};
+
+        // Create attachment.
+        auto answer{connection.post(masto::API::v1::media,
+                                    {
+                                        {"file", string("@file:") += filename},
+                                        {"description", "Test."}
+                                    })};
+
+        // Get the ID of the attachment.
+        // You normally would use a JSON parser, of course. I don't use one
+        // because I don't want to add a dependency just for an example.
+        const auto pos{answer.body.find(R"("id":")") + 6};
+        const auto endpos{answer.body.find(R"(",)", pos)};
+        const auto media_id{answer.body.substr(pos, endpos - pos)};
+        cout << "Attachment has ID: " << media_id << endl;
+
+        // Post the status. Note that “media_ids” always has to be a vector.
+        answer = connection.post(masto::API::v1::statuses,
+                                 {
+                                     {"status", "Attachment test."},
+                                     {"media_ids",
+                                      vector<string_view>{media_id}}
+                                 });
+        if (answer)
+        {
+            cout << "Successfully posted " << filename << ".\n";
+        }
+        else
+        {
+            if (answer.curl_error_code == 0)
+            {
+                // If it is no libcurl error, it must be an HTTP error.
+                cerr << "HTTP status: " << answer.http_status << endl;
+            }
+            else
+            {
+                // Network errors like “Couldn't resolve host.”.
+                cerr << "libcurl error " << to_string(answer.curl_error_code)
+                     << ": " << answer.error_message << endl;
+            }
+        }
+    }
+    catch (const masto::CURLException &e)
+    {
+        // Only libcurl errors that are not network errors will be thrown.
+        // There went probably something wrong with the initialization.
+        cerr << e.what() << endl;
+    }
+
+    return 0;
+}

include/mastodonpp.hpp

@@ -70,7 +70,6 @@
  *  @subsection input Input
  *
  *  * 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.
  *
@@ -102,6 +101,7 @@
  *  @example example01_instance_info.cpp
  *  @example example02_streaming.cpp
  *  @example example03_post_status.cpp
+ *  @example example04_post_with_attachment.cpp
  */
 
 /*!