Update body parsing and file streaming exemples

examples/FileStreaming.js

@@ -0,0 +1,102 @@
+// This is an example of streaming files
+
+const uWS = require('../dist/uws.js');
+const fs = require('fs');
+
+const port = 9001;
+const bigFileName = 'absolutPathTo/bigVideo.mp3';
+const bigFileSize = fs.statSync(bigFileName).size;
+console.log('Video size is: '+ bigFileSize +' bytes');
+
+// Stream data to res
+/** @param {import('node:Stream').Readable} readStream */
+const streamData = (res, readStream, totalSize, onFinished) => {
+    let chunkBuffer; // Actual chunk being streamed
+    let totalOffset = 0; // Actual chunk offset
+    const sendChunkBuffer = () => {
+        const [ok, done] = res.tryEnd(chunkBuffer, totalSize);
+        if (done) {
+            // Streaming finished
+            readStream.destroy();
+            onFinished();
+        } else if (ok) {
+            // Chunk send success
+            totalOffset += chunkBuffer.length;
+            // Resume stream if it was paused
+            readStream.resume();
+        } else {
+            // Chunk send failed (client backpressure)
+            // onWritable will be called once client ready to receive new chunk
+            // Pause stream
+            readStream.pause();
+        }
+        return ok;
+    };
+
+    // Attach onAborted handler because streaming is async
+    res.onAborted(() => {
+        readStream.destroy();
+        onFinished();
+    });
+
+    // Register onWritable callback
+    // Will be called to drain client backpressure
+    res.onWritable((offset) => {
+        const offsetDiff = offset - totalOffset;
+        if (offsetDiff) {
+            // If start of the chunk was successfully sent
+            // We only send the missing part
+            chunkBuffer = chunkBuffer.subarray(offsetDiff);
+            totalOffset = offset;
+        }
+        // Always return if resend was successful or not
+        return sendChunkBuffer();
+    });
+
+    // Register callback for stream events
+    readStream.on('error', (err) => {
+        console.log('Error reading file: '+ err);
+        // res.close calls onAborted callback
+        res.close();
+    }).on('data', (newChunkBuffer) => {
+        chunkBuffer = newChunkBuffer;
+        // Cork before sending new chunk
+        res.cork(sendChunkBuffer);
+    });
+};
+
+let lastStreamIndex = 0;
+let openStreams = 0;
+
+const app = uWS./*SSL*/App({
+    key_file_name: 'misc/key.pem',
+    cert_file_name: 'misc/cert.pem',
+    passphrase: '1234'
+}).get('/bigFile', (res, req) => {
+    const streamIndex = ++ lastStreamIndex;
+    console.log('Stream ('+ streamIndex +') was opened, openStreams: '+ (++ openStreams));
+    res.writeHeader('Content-Type', 'video/mpeg');
+    // Create read stream with fs.createReadStream
+    streamData(res, fs.createReadStream(bigFileName), bigFileSize, () => {
+        // On streaming finished (success/error/onAborted)
+        console.log('Stream ('+ streamIndex +') was closed, openStreams: '+ (-- openStreams));
+    });
+
+}).get('/smallFile', (res, req) => {
+    // !! Use this only for small files !!
+    // May cause server backpressure and bad performance
+    // For bigger files you have to use streaming
+    try {
+        const fileBuffer = fs.readFileSync('absolutPathTo/smallData.json');
+        res.writeHeader('Content-Type', 'application/json').end(fileBuffer);
+    } catch (err) {
+        console.log('Error reading file: '+ err);
+        res.writeStatus('500 Internal Server Error').end();
+    }
+}).listen(port, (token) => {
+    if (token) {
+        console.log('Listening to port ' + port);
+    } else {
+        console.log('Failed to listen to port ' + port);
+    }
+});

examples/ParseJsonOrFormBody.js

@@ -0,0 +1,89 @@
+// Simple example of parsing JSON body or URL-encoded form
+
+const querystring = require('node:querystring');
+const uWS = require('../dist/uws.js');
+const port = 9001;
+
+// Helper function for parsing JSON body
+const parseJSONBody = (res, callback) => {
+    let buffer = Buffer.alloc(0);
+    // Register data callback
+    res.onData((ab, isLast) => {
+        buffer = Buffer.concat([buffer, Buffer.from(ab)]);
+        if (isLast) {
+            let parsedJson;
+            try { parsedJson = JSON.parse(buffer.toString()); }
+            catch { parsedJson = null; }
+            callback(parsedJson);
+        }
+    });
+};
+
+// Helper function for parsing URL-encoded form body
+const parseFormBody = (res, callback) => {
+    let buffer = Buffer.alloc(0);
+    // Register data callback
+    res.onData((ab, isLast) => {
+        buffer = Buffer.concat([buffer, Buffer.from(ab)]);
+        if (isLast) {
+            let parsedForm;
+            try { parsedForm = querystring.parse(buffer.toString()); }
+            catch { parsedForm = null; }
+            callback(parsedForm);
+        }
+    });
+};
+
+const app = uWS./*SSL*/App({
+    key_file_name: 'misc/key.pem',
+    cert_file_name: 'misc/cert.pem',
+    passphrase: '1234'
+}).get('/jsonAPI', (res, req) => {
+    // Attach onAborted handler because body parsing is async
+    res.onAborted(() => {
+        res.aborted = true;
+    });
+
+    parseJSONBody(res, (object) => {
+        if (res.aborted) return;
+        if (!object) {
+            console.log('Invalid JSON or no data at all!');
+            res.cork(() => { // Cork because async
+                res.writeStatus('400 Bad Request').end();
+            });
+        } else {
+            console.log('Valid JSON: ');
+            console.log(object);
+            res.cork(() => {
+                res.end('Thanks for this json!');
+            });
+        }
+    });
+}).post('/formPost', (res, req) => {
+    // Attach onAborted handler because body parsing is async
+    res.onAborted(() => {
+        res.aborted = true;
+    });
+
+    parseFormBody(res, (form) => {
+        if (res.aborted) return;
+        if (!form || !form.myData) {
+            console.log('Invalid form body or no data at all!');
+            res.cork(() => { // Cork because async
+                res.end('Invalid form body');
+            });
+        } else {
+            console.log('Valid form body: ');
+            console.log(form);
+            res.cork(() => {
+                res.end('Thanks for your data!');
+            });
+        }
+    });
+}).listen(port, (token) => {
+    if (token) {
+        console.log('Listening to port ' + port);
+    } else {
+        console.log('Failed to listen to port ' + port);
+    }
+});