OF_Async_HTTPRequest.h

#include "ofMain.h"

class ofApp : public ofBaseApp {
  
  static const std::string kEndpoint;
  static const std::string kRequestLabel; // for testing
  
  std::unordered_map<std::string, std::function<void(const ofHttpResponse &)>> handler;
  std::vector<int> request_history;
  
  
public:
  
  void myCallBack(const ofHttpResponse & res) {
    
    // https://ja.wikipedia.org/wiki/HTTP%E3%82%B9%E3%83%86%E3%83%BC%E3%82%BF%E3%82%B9%E3%82%B3%E3%83%BC%E3%83%89
    
    if (res.status >= 500) {
      ofLogError("Server error") << res.error;
    }
    else if (res.status >= 400) {
      ofLogError("Client error") << res.error;
    }
    else {
      const std::string label = res.request.name;
      const auto & pair = handler.find(label);
      if (pair != handler.end()) {
        const auto & callback = pair->second;
        callback(res);
      } else {
        ofLogError() << "handler not found:" << label;
      }
    }
  }
  
  
  // ---
  
  
  void setup() {
    ofSetFrameRate(60);
    ofSetVerticalSync(true);
    
    handler[kRequestLabel] = [&](const ofHttpResponse & res){
      const auto position = std::find(request_history.begin(),
                                      request_history.end(),
                                      res.request.getId());
      assert(position != request_history.end());
      assert(kRequestLabel == res.request.name);
      
      request_history.erase(position);
      
      std::ostringstream report;
      report << "request name: " << res.request.name << endl;
      report << "request id: " << res.request.getId() << endl;
      report << "response data: " << res.data << endl;
      cout << report.str() << endl;
    };
    ofAddListener(ofURLResponseEvent(), this, &ofApp::myCallBack);
  }
  
  void draw() {
    const float speed = ofGetElapsedTimef()  * 3;
    const float radius = sin(speed) * 10. + 100.;
    ofDrawCircle(ofGetWidth()/2, ofGetHeight()/2, radius);
    
    std::ostringstream report;
    report << "Request ID:";
    for (const auto &history : request_history) {
      report << endl << history;
    }
    const ofColor color = request_history.empty() ? ofColor::gray : ofColor::limeGreen;
    ofDrawBitmapStringHighlight(report.str(), 30, 30, color);
  }
  
  void keyPressed(int key) {
    if (key == 'l') {
      try {
        const int request_id = ofLoadURLAsync(kEndpoint, kRequestLabel);
        request_history.push_back(request_id);
      } catch (std::exception e) {
        ofLogError("ofLoadURLAsync error") << e.what();
      }
    }
  }
  
  void exit() {
    ofRemoveListener(ofURLResponseEvent(), this, &ofApp::myCallBack);
  }
};


const std::string ofApp::kEndpoint  = "http://date.jsontest.com/";
const std::string ofApp::kRequestLabel  = "my_request";


#pragma mark -
#pragma mark main
int main(){
  ofGLWindowSettings settings;
  settings.width = 500;
  settings.height = 500;
  settings.setGLVersion(3, 2);
  ofCreateWindow(settings);
  
  ofRunApp(new ofApp());
}

0.7.3からAsyncLoadが追加されてた模様