accept uri as input to demo node and node-canvas

demo/node-canvas.js

@@ -22,6 +22,9 @@ async function image(input) {
   const c = canvas.createCanvas(img.width, img.height);
   const ctx = c.getContext('2d');
   ctx.drawImage(img, 0, 0, img.width, img.height);
+  // const out = fs.createWriteStream('test.jpg');
+  // const stream = c.createJPEGStream({ quality: 0.6, progressive: true, chromaSubsampling: true });
+  // stream.pipe(out);
   return c;
 }
 
@@ -80,7 +83,7 @@ async function main() {
     log.info('Processed', numImages, 'images in', Math.trunc(parseInt(t1 - t0) / 1000 / 1000), 'ms');
   } else {
     const param = process.argv[2];
-    if (fs.existsSync(param)) {
+    if (fs.existsSync(param) || param.startsWith('http:') || param.startsWith('https:')) {
       const c = await image(param);
       const result = await detect(c);
       log.data('Image:', param, 'Detected faces:', result.length);

demo/node.js

@@ -6,6 +6,8 @@ const path = require('path');
 // eslint-disable-next-line import/no-extraneous-dependencies, node/no-unpublished-require
 const log = require('@vladmandic/pilogger');
 // eslint-disable-next-line import/no-extraneous-dependencies, node/no-unpublished-require
+const fetch = require('node-fetch').default;
+// eslint-disable-next-line import/no-extraneous-dependencies, node/no-unpublished-require
 const tf = require('@tensorflow/tfjs-node');
 const faceapi = require('../dist/face-api.node.js'); // this is equivalent to '@vladmandic/faceapi'
 
@@ -15,14 +17,35 @@ const minConfidence = 0.15;
 const maxResults = 5;
 let optionsSSDMobileNet;
 
-async function image(img) {
-  const buffer = fs.readFileSync(img);
-  const decoded = tf.node.decodeImage(buffer);
-  const casted = decoded.toFloat();
-  const result = casted.expandDims(0);
-  decoded.dispose();
-  casted.dispose();
-  return result;
+async function image(input) {
+  // read input image file and create tensor to be used for processing
+  let buffer;
+  log.info('Loading image:', input);
+  if (input.startsWith('http:') || input.startsWith('https:')) {
+    const res = await fetch(input);
+    if (res && res.ok) buffer = await res.buffer();
+    else log.error('Invalid image URL:', input, res.status, res.statusText, res.headers.get('content-type'));
+  } else {
+    buffer = fs.readFileSync(input);
+  }
+
+  // decode image using tfjs-node so we don't need external depenencies
+  // can also be done using canvas.js or some other 3rd party image library
+  if (!buffer) return {};
+  const tensor = tf.tidy(() => {
+    const decode = faceapi.tf.node.decodeImage(buffer, 3);
+    let expand;
+    if (decode.shape[2] === 4) { // input is in rgba format, need to convert to rgb
+      const channels = faceapi.tf.split(decode, 4, 2); // tf.split(tensor, 4, 2); // split rgba to channels
+      const rgb = faceapi.tf.stack([channels[0], channels[1], channels[2]], 2); // stack channels back to rgb and ignore alpha
+      expand = faceapi.tf.reshape(rgb, [1, decode.shape[0], decode.shape[1], 3]); // move extra dim from the end of tensor and use it as batch number instead
+    } else {
+      expand = faceapi.tf.expandDims(decode, 0);
+    }
+    const cast = faceapi.tf.cast(expand, 'float32');
+    return cast;
+  });
+  return tensor;
 }
 
 async function detect(tensor) {
@@ -97,7 +120,7 @@ async function main() {
     log.info('Processed', dir.length, 'images in', Math.trunc(parseInt(t1 - t0) / 1000 / 1000), 'ms');
   } else {
     const param = process.argv[2];
-    if (fs.existsSync(param)) {
+    if (fs.existsSync(param) || param.startsWith('http:') || param.startsWith('https:')) {
       const tensor = await image(param);
       const result = await detect(tensor);
       // const result = await detectPromise(null);

package.json

@@ -53,18 +53,19 @@
     "canvas": "^2.7.0",
     "chokidar": "^3.5.1",
     "dayjs": "^1.10.4",
-    "esbuild": "^0.11.12",
-    "eslint": "^7.24.0",
+    "esbuild": "^0.11.14",
+    "eslint": "^7.25.0",
     "eslint-config-airbnb-base": "^14.2.1",
     "eslint-plugin-import": "^2.22.1",
     "eslint-plugin-json": "^2.1.2",
     "eslint-plugin-node": "^11.1.0",
     "eslint-plugin-promise": "^5.1.0",
+    "node-fetch": "^2.6.1",
     "rimraf": "^3.0.2",
     "seedrandom": "^3.0.5",
     "simple-git": "^2.38.0",
     "tslib": "^2.2.0",
-    "typedoc": "^0.20.35",
+    "typedoc": "^0.20.36",
     "typescript": "^4.2.4"
   }
 }