Update pr2043 urlFileDownloader: progress event + example

.gitignore

@@ -194,3 +194,4 @@ scripts/templates/vs2019/emptyExample.vcxproj.user
 libs/openFrameworksCompiled/project/android/build-*/
 
 
+examples/utils/urlFileLoaderExample/bin/data

examples/utils/urlFileLoaderExample/src/main.cpp

@@ -0,0 +1,13 @@
+#include "ofMain.h"
+#include "ofApp.h"
+
+//========================================================================
+int main() {
+	ofGLWindowSettings settings;
+	settings.setSize(720, 240);
+	settings.windowMode = OF_WINDOW;
+
+	auto window = ofCreateWindow(settings);
+	ofRunApp(window, std::make_shared<ofApp>());
+	ofRunMainLoop();
+}

examples/utils/urlFileLoaderExample/src/ofApp.cpp

@@ -0,0 +1,36 @@
+#include "ofApp.h"
+
+//--------------------------------------------------------------
+void ofApp::setup() {
+	ofSetWindowTitle("URL file loader progress");
+	ofSetBackgroundColor(30);
+
+	const std::string url = "https://raw.githubusercontent.com/openframeworks/openFrameworks/master/examples/graphics/fontShapesExample/bin/data/Batang.ttf";
+	ofHttpRequest request(url, ofToDataPath("Batang.ttf"), true);
+	request.progressCallback = [this](const ofHttpRequest &, float value) {
+		progress.store(value);
+	};
+	request.done = [this](const ofHttpResponse & response) {
+		status = response.status;
+		finished = true;
+	};
+	loader.handleRequestAsync(request);
+}
+
+//--------------------------------------------------------------
+void ofApp::draw() {
+	const float value = progress.load();
+	const float width = ofGetWidth() - 80.0f;
+
+	ofSetColor(90);
+	ofDrawRectangle(40, 100, width, 24);
+	ofSetColor(70, 180, 255);
+	ofDrawRectangle(40, 100, width * value, 24);
+
+	ofSetColor(255);
+	ofDrawBitmapString("Downloading Batang.ttf", 40, 70);
+	ofDrawBitmapString(ofToString(value * 100.0f, 1) + "%", 40, 150);
+	if (finished) {
+		ofDrawBitmapString("Finished with HTTP status " + ofToString(status), 40, 185);
+	}
+}

examples/utils/urlFileLoaderExample/src/ofApp.h

@@ -0,0 +1,17 @@
+#pragma once
+
+#include "ofMain.h"
+
+#include <atomic>
+
+class ofApp : public ofBaseApp {
+public:
+	void setup() override;
+	void draw() override;
+
+private:
+	ofURLFileLoader loader;
+	std::atomic<float> progress{ 0.0f };
+	bool finished = false;
+	int status = 0;
+};

libs/openFrameworks/utils/ofURLFileLoader.cpp

@@ -348,18 +348,12 @@ size_t readBody_cb(void * ptr, size_t size, size_t nmemb, void * userdata) {
 	}
 	return 0; /* no more data left to deliver */
 }
-int progress_cb(void* ptr, curl_off_t dltotal, curl_off_t dlnow, curl_off_t ultotal, curl_off_t ulnow) {
-	auto & request = *static_cast<ofHttpRequest*>(ptr);
-	if (request.progressCallback) {
-		float progress = 0.0f;
-		if (request.method == ofHttpRequest::GET && dltotal > 0) {
-			progress = (float)dlnow / (float)dltotal;
-			// note: we may want to support upload and download for POST
-		} else if ((request.method == ofHttpRequest::PUT || request.method == ofHttpRequest::POST) && ultotal > 0) {
-			progress = (float)ulnow / (float)ultotal;
-		}
-
-		request.progressCallback(request, progress);
+int transferProgress_cb(void * userdata, curl_off_t downloadTotal, curl_off_t downloaded, curl_off_t uploadTotal, curl_off_t uploaded) {
+	const auto & request = *static_cast<const ofHttpRequest *>(userdata);
+	if (request.method == ofHttpRequest::GET && downloadTotal > 0) {
+		request.progressCallback(request, static_cast<float>(downloaded) / static_cast<float>(downloadTotal));
+	} else if ((request.method == ofHttpRequest::PUT || request.method == ofHttpRequest::POST) && uploadTotal > 0) {
+		request.progressCallback(request, static_cast<float>(uploaded) / static_cast<float>(uploadTotal));
 	}
 	return 0;
 }
@@ -536,13 +530,13 @@ ofHttpResponse ofURLFileLoaderImpl::handleRequest(const ofHttpRequest & request)
 	// start request and receive response
 	ofHttpResponse response(request, 0, "");
 	CURLcode err = CURLE_OK;
-	
+
 	if (request.progressCallback) {
-		curl_easy_setopt(curl.get(), CURLOPT_XFERINFOFUNCTION, progress_cb);
+		curl_easy_setopt(curl.get(), CURLOPT_XFERINFOFUNCTION, transferProgress_cb);
 		curl_easy_setopt(curl.get(), CURLOPT_XFERINFODATA, &request);
 		curl_easy_setopt(curl.get(), CURLOPT_NOPROGRESS, 0L);
 	}
-	
+
 	if (request.saveTo) {
 		ofFile saveTo(request.name, ofFile::WriteOnly, true);
 		curl_easy_setopt(curl.get(), CURLOPT_WRITEDATA, &saveTo);

libs/openFrameworks/utils/ofURLFileLoader.h

@@ -23,7 +23,8 @@ class ofHttpRequest {
 	std::string body; ///< POST body data
 	std::string contentType; ///< POST data mime type
 	std::function<void(const ofHttpResponse &)> done;
-	std::function<void(const ofHttpRequest &, float)> progressCallback = nullptr; ///< pass a function for progress of download
+	/// the URL loader's worker thread. range [0, 1]
+	std::function<void(const ofHttpRequest &, float)> progressCallback = nullptr; // it reports upload/download progress. Asynchronous requests invoke this callback 
 	size_t timeoutSeconds = 0;
 	bool headerOnly = false;