PDF Form Handling with Fileforge

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import { readFileSync, writeFileSync } from "fs";
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import { FormData, Blob } from "formdata-node";
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// set-up the API key and the path to the document
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const API_KEY = "XXX-API-KEY-XXX";
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const documentPath = "./form.pdf";
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const documentBuffer = readFileSync(documentPath);
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// create a new FormData object and append the file to it
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const payload = new FormData();
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payload.append("file", new Blob([documentBuffer]), "form.pdf");
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/**
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 * Detects fields in a programmatic way. Returns a list of all available fields, field types and options (if any).
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 */
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const detectFields = await fetch("https://api.fileforge.com/pdf/form/detect", {
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  method: "POST",
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  body: payload,
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  headers: {
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    "X-API-Key": API_KEY,
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  },
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});
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// get the fields as JSON
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const fields = await detectFields.json();
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// log the first 20 fields to the console
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console.log(fields.slice(0, 20));

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[
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  {
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    name: 'undefined',
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    required: false,
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    readOnly: false,
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    locations: [ [Object] ],
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    type: 'PDFCheckBox',
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    isChecked: false
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  },
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  {
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    name: 'Admissions and Records Enrollment Services at',
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    required: false,
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    readOnly: false,
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    locations: [ [Object] ],
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    type: 'PDFTextField',
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    isPassword: false,
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    isRichFormatted: false,
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    isScrollable: true,
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    isCombed: false,
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    isMultiline: false,
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    isFileSelector: false
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  },
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  {
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    name: 'Name',
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    required: false,
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    readOnly: false,
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    locations: [ [Object] ],
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    type: 'PDFTextField',
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    isPassword: false,
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    isRichFormatted: false,
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    isScrollable: true,
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    isCombed: false,
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    isMultiline: false,
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    isFileSelector: false
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  },
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    ...
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]

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/**
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 * Use this to write a debug PDF with comments highlighting each field name and position.
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 * This is best open in Acrobat Reader. Note: the fields themselves may hide the highlight.
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 * To view the tags anyway, open the comments pane in Acrobat Reader.
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 */
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const markFields = await fetch("https://api.fileforge.com/pdf/form/mark", {
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  method: "POST",
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  body: payload,
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  headers: {
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    "X-API-Key": API_KEY,
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  },
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});
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if (markFields.status !== 201) {
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  throw new Error(await markFields.text());
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}
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// write the debug PDF to disk
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writeFileSync("./form-debug.pdf", Buffer.from(await markFields.arrayBuffer()));

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payload.append(
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  "options",
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  new Blob(
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    [
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      JSON.stringify({
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        /**
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         * The fields to fill. The name must match the field name exactly. There are various options depending on the field type.
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         */
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        fields: [
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          {
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            name: "Name",
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            type: "PDFTextField",
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            value: "Auguste Lefevre Grunewald",
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          },
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          {
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            name: "Office of Public Stewardship",
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            type: "PDFCheckBox",
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            checked: true,
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          },
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          {
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            name: "Phone Number",
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            type: "PDFTextField",
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            value: "+1 415 123-1234",
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          },
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        ],
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      }),
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    ],
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    {
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      type: "application/json",
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    }
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  )
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);
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// fill the form
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const filledForm = await fetch("https://api.fileforge.com/pdf/form/fill", {
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  method: "POST",
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  body: payload,
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  headers: {
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    "X-API-Key": API_KEY,
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  },
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});
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// check for errors
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if (filledForm.status !== 201) {
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  throw new Error(await filledForm.text());
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}
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// write the filled form to disk
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writeFileSync("./form-filled.pdf", Buffer.from(await filledForm.arrayBuffer()));