PDF Filler Stream

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> This is a fork of the pdf-filler package, modified to return promises and readable streams, by piping data in/out of a spawned pdftk process instead of temporarily writing files to disk.

> The goal is cleaner integration, in eg. a microservices context, where it is preferable not to write multiple temporary files to disk and where you may wish to stream the generated pdf directly to a service like AWS.

A node.js PDF form field data filler and FDF generator toolkit. This essentially is a wrapper around the PDF Toolkit library PDF ToolKit.

As of version 4.0.0, this library now targets pdftk-java, a modern fork of pdftk.

Quick start

You must first have pdftk (from pdftk-java, found here) installed correctly on your platform.

Then, install this library:

``bash
npm install @sparticuz/pdffiller --save
`

Note for AWS Lambda users, you may use a pdftk layer, found here

Examples

#### 1.Fill PDF with existing FDF Data

`javascript
import fillForm from "@sparticuz/pdffiller";

const sourcePDF = "test/test.pdf";

const data = {
last_name: "John",
first_name: "Doe",
date: "Jan 1, 2013",
football: "Off",
baseball: "Yes",
basketball: "Off",
hockey: "Yes",
nascar: "Off",
};

const output = await fillForm(sourcePDF, data);
// output will be instance of stream.Readable
`

This will take the test.pdf, fill the fields with the data values and stream a filled in, read-only PDF.

A chainable convenience method toFile is attached to the response, if you simply wish to write the stream to a file with no fuss:

`javascript
fillForm(sourcePDF, data)
.toFile("outputFile.PDF")
.then(() => {
// your file has been written
})
.catch((err) => {
console.log(err);
});
`

You could also stream the resulting data directly to AWS, doing something like this with an instantiated s3 client:

`javascript
fillForm(sourcePDF, data)
.then((outputStream) => {
const Body = outputStream;
const Bucket = "some-bucket";
const Key = "myFancyNewFilledPDF";
const ContentType = "application/pdf";

const uploader = new AWS.S3.ManagedUpload({
params: { Bucket, Key, Body, ContentType },
service: s3,
});

uploader.promise().then((data) => {
/ do something with AWS response /
});
})
.catch((err) => {
console.log(err);
});
`

Calling fillForm() with shouldFlatten = false will leave any unmapped fields still editable, as per the pdftk command specification.

`javascript

const shouldFlatten = false;

fillForm(sourcePDF, data, shouldFlatten)
.then((outputStream) {
// etc, same as above
})
`

#### 1a. UTF-8 Characters in PDF forms

In order to have accents in the form fields of a form, pdftk needs the needs_appearances flag appended. Unfortunantly, if that flag is added, flatten is unable to be used. (Bug here: https://gitlab.com/pdftk-java/pdftk/-/issues/128)

`javascript

const shouldFlatten = false;

fillForm(sourcePDF, data, ["needs_appearances"])
.then((outputStream) {
// etc, same as above
})
`

#### 2. Generate FDF Template from PDF

`javascript
import { generateFDFTemplate } from "@sparticuz/pdffiller";

const sourcePDF = "test/test.pdf";

const FDF_data = generateFDFTemplate(sourcePDF)
.then((fdfData) => {
console.log(fdfData);
})
.catch((err) => {
console.log(err);
});
`

This will print out this

`json
{
"last_name": "",
"first_name": "",
"date": "",
"football": "",
"baseball": "",
"basketball": "",
"hockey": "",
"nascar": ""
}
`

#### 3. Map form fields to PDF fields

`javascript
import { mapForm2PDF } from "@sparticuz/pdffiller";

const conversionMap = {
lastName: "last_name",
firstName: "first_name",
Date: "date",
footballField: "football",
baseballField: "baseball",
bballField: "basketball",
hockeyField: "hockey",
nascarField: "nascar",
};

const FormFields = {
lastName: "John",
firstName: "Doe",
Date: "Jan 1, 2013",
footballField: "Off",
baseballField: "Yes",
bballField: "Off",
hockeyField: "Yes",
nascarField: "Off",
};

mapForm2PDF(data, convMap).then((mappedFields) => {
console.log(mappedFields);
});
`

This will print out the object below.

`json
{
"last_name": "John",
"first_name": "Doe",
"date": "Jan 1, 2013",
"football": "Off",
"baseball": "Yes",
"basketball": "Off",
"hockey": "Yes",
"nascar": "Off"
}
`

#### 4. Convert fieldJson to FDF data

`javascript
import { convFieldJson2FDF } from '@sparticuz/pdffiller';

const fieldJson = [
{
"title" : "last_name",
"fieldfieldType": "Text",
"fieldValue": "Doe"
},
{
"title" : "first_name",
"fieldfieldType": "Text",
"fieldValue": "John"
},
{
"title" : "date",
"fieldType": "Text",
"fieldValue": "Jan 1, 2013"
},
{
"title" : "football",
"fieldType": "Button",
"fieldValue": false
},
{
"title" : "baseball",
"fieldType": "Button",
"fieldValue": true
},
{
"title" : "basketball",
"fieldType": "Button"
"fieldValue": false
},
{
"title" : "hockey",
"fieldType": "Button"
"fieldValue": true
},
{
"title" : "nascar",
"fieldType": "Button"
"fieldValue": false
}
];


const FDFData = convFieldJson2FDF(data);

console.log(FDFData)
`

This will print out:

`json
{
"last_name" : "John",
"first_name" : "Doe",
"date" : "Jan 1, 2013",
"football" : "Off",
"baseball" : "Yes",
"basketball" : "Off",
"hockey" : "Yes",
"nascar" : "Off"
};
``