node.js 编译的 pkg 不会运行（但从节点运行）

Question

I have a simple program I am working on with node.js, the idea was to fetch some websites and show a report, it is for testing web content filtering in a company.

I started struggling with taking the screenshots of the website, when I run my code as node index.js it works perfectly, it outputs 'google.png' and contains a screenshot of the website (Just as in the screenshot-stream example). However, I compile it using npx pkg index.js -t linux and it starts giving me errors on execution.

I reduced the program to only this:

const fs = require('fs')
const screenshot = require('screenshot-stream');

const stream = screenshot('http://google.com', '900x180', {crop: true});

stream.pipe(fs.createWriteStream('google.png'));

I run node index.js and it generates the image. However after compiling (and adding the phantomjs to the phantom folder as warned by npx), I get an error:

./index 
events.js:183
      throw er; // Unhandled 'error' event
      ^

Error: Can't open '/snapshot/screenshots/node_modules/screenshot-stream/stream.js'
    at LineStream.module.exports.byline.on.data (/snapshot/screenshots/node_modules/screenshot-stream/index.js:77:16)
    at emitOne (events.js:116:13)
    at LineStream.emit (events.js:211:7)
    at addChunk (_stream_readable.js:263:12)
    at readableAddChunk (_stream_readable.js:250:11)
    at LineStream.Readable.push (_stream_readable.js:208:10)
    at LineStream.Transform.push (_stream_transform.js:147:32)
    at LineStream._pushBuffer (/snapshot/screenshots/node_modules/byline/lib/byline.js:125:17)
    at LineStream._transform (/snapshot/screenshots/node_modules/byline/lib/byline.js:116:8)
    at LineStream.Transform._read (_stream_transform.js:186:10)

I am using screenshot-stream@4.2.0, npm@6.4.1, pkg@4.3.4

Any help is greatly appreciated

Answer 1

Debugged over this code and found that screenshot-stream module uses

path.join(__dirname, 'stream.js')

to pass as an argument to call phantomjs as a child process.

When runing directly on node this works fine but when compiled with pkg, this child process has not access to the snapshot filesystem created by this packager.

I found a workaround: modifying screenshot-stream/index.js:

On line 45:

Replace __dirname with './' and place stream.js on the binary working directory and should work fine.