How to pipe a stream using pdfkit with node js

Question

Before PDFkit 0.5 - the following worked for me (generating a pdf via pdfkit/printing via ipp to CUPS):

var ipp = require("ipp");
var PDFDocument = require("pdfkit");

var doc = new PDFDocument;
doc.text("Hello World");

doc.output(function(pdf)){
    var printer = ipp.Printer("http://127.0.0.1:631/printers/1");
    var file = {
        "operation-attributes-tag":{
            "requesting-user-name": "User",
        "job-name": "Print Job",
        "document-format": "application/pdf"
        },
        data: new Buffer(pdf, "binary")
    };

    printer.execute("Print-Job", file, function (err, res) {
        console.log("Printed: "+res.statusCode);
    });
}

As of PDFkit 0.5 - the output method is deprecated - but I can't seem to find an example of using the new pipe method with my scenario. If I'm not using a browser, do I still need a module like blob-stream?

Solution

Since pdfkit PDFDocument now is a stream, you have to buffer the data coming from the buffer:

var ipp = require("ipp");
var PDFDocument = require("pdfkit");

var doc = new PDFDocument;
doc.text("Hello World");

var buffers = [];
doc.on('data', buffers.push.bind(buffers));
doc.on('end', function () {
    var printer = ipp.Printer("http://127.0.0.1:631/printers/1");
    var file = {
        "operation-attributes-tag":{
            "requesting-user-name": "User",
        "job-name": "Print Job",
        "document-format": "application/pdf"
        },
        data: Buffer.concat(buffers)
    };

    printer.execute("Print-Job", file, function (err, res) {
        console.log("Printed: "+res.statusCode);
    });
});
doc.end();

Or you can use something like concat-stream module:

var ipp = require("ipp");
var PDFDocument = require("pdfkit");
var concat = require("concat-stream");

var doc = new PDFDocument;
doc.text("Hello World");

doc.pipe(concat(function (data) {
    var printer = ipp.Printer("http://127.0.0.1:631/printers/1");
    var file = {
        "operation-attributes-tag":{
            "requesting-user-name": "User",
        "job-name": "Print Job",
        "document-format": "application/pdf"
        },
        data: data
    };

    printer.execute("Print-Job", file, function (err, res) {
        console.log("Printed: "+res.statusCode);
    });
}));
doc.end();

Comments

[Josiah]

Worked perfectly! Thanks!

[jeremywoertink]

This works for me as well. Be sure to call doc.end() to actually fire off the end event. I've added an edit for anyone that comes across this new to the library.

[Rogério Oliveira]

Hi there! I would like to use that suggestion in my code. Unfortunately, I've a problem: when I try to save the binary data performing fs.writeFileSync('test.pdf', buffers) to get its content back, it generates a corrupted file. @Josiah some suggestion? Thank you a lot.

[Farid Nouri Neshat]

Yeah, you can concatenate the buffers into one buffer and only then you can pass it to fs.writeFileSync: fs.writeFileSync('test.pdf', Buffer.concat(buffers)). Of course to do it properly you should be streaming to it and you wouldn't need buffering: doc.pipe (fs.createWriteStream('test.pdf'))

[Luke Brown]

This was really helpful using doc.on('end'). Spent 4 hours trying to get this working and your solution fixed it. Saves me creating a temp file to upload elsewhere, whereas now I can just send Buffer directly.