Dump the form values from a PDF

A small tool for fetching form content from a PDF.

% ./read_form_fields --help
Get the form field contents from a PDF. It uses poppler. The output looks
like PDFtk's dump_data_fields_utf8. Supports AcroForm & XfaForm PDF forms.

Usage:
  read_form_fields (<file> | -)
  read_form_fields --help

Options:
  <file> is the name of the file
  -h --help       Show this screen.

Details on output:
  The output resembles PDFtk's. Each line consists of one of:
  - A separator '---' that separate two fields
  - FieldType: Choice | Button | Text | Signature | Unknown
  - FieldName: <text> (only with Text, Choice, Button)
  - FieldMaxLength: <integer> (only with Text)
  - FieldStateOption: <text> (for Text & Choice) | Off | Yes (Button)

Notes:
  1) The order of appearance is different from PDFtk's. This program will
     show the fields by order of appearance in each page.
  2) Some field labels aren't supported: FieldValueDefault, FieldNameAlt,
     FieldFlags, FieldJustification. They aren't in the Poppler Glib API.
  3) Sometimes the unicode point 'U+FEFF which corresponds to the BOM was
     showing in the field values and names. So I strip 'U+FEFF' from
     values/names before printing.

$ ./read_form_fields form.pdf
FieldType: Choice
FieldName: Favourite Colour List Box
FieldStateOption: Black
FieldStateOption: Brown
FieldStateOption: Red
FieldStateOption: Orange
FieldStateOption: Yellow
FieldStateOption: Green
FieldStateOption: Blue
FieldStateOption: Violet
FieldStateOption: Grey
FieldStateOption: White
---
FieldType: Button
FieldName: Language 5 Check Box
FieldValue: Off
FieldStateOption: Off
FieldStateOption: Yes
---
FieldType: Button
FieldName: Language 4 Check Box
FieldValue: Off
FieldStateOption: Off
FieldStateOption: Yes
---
FieldType: Button
FieldName: Language 3 Check Box
FieldValue: Off
FieldStateOption: Off
FieldStateOption: Yes
---
FieldType: Button
FieldName: Language 2 Check Box
FieldValue: Yes
FieldStateOption: Off
FieldStateOption: Yes
---
FieldType: Button
FieldName: Language 1 Check Box
FieldValue: Off
FieldStateOption: Off
FieldStateOption: Yes
---
FieldType: Button
FieldName: Driving License Check Box
FieldValue: Off
FieldStateOption: Off
FieldStateOption: Yes
---
FieldType: Text
FieldName: Height Formatted Field
FieldValue: 150
FieldMaxLength: 20
---
FieldType: Choice
FieldName: Gender List Box
FieldStateOption: Man
FieldStateOption: Woman
---
FieldType: Choice
FieldName: Country Combo Box
FieldStateOption: Austria
FieldStateOption: Belgium
FieldStateOption: Britain
FieldStateOption: Bulgaria
FieldStateOption: Croatia
FieldStateOption: Cyprus
FieldStateOption: Czech-Republic
FieldStateOption: Denmark
FieldStateOption: Estonia
FieldStateOption: Finland
FieldStateOption: France
FieldStateOption: Germany
FieldStateOption: Greece
FieldStateOption: Hungary
FieldStateOption: Ireland
FieldStateOption: Italy
FieldStateOption: Latvia
FieldStateOption: Lithuania
FieldStateOption: Luxembourg
FieldStateOption: Malta
FieldStateOption: Netherlands
FieldStateOption: Poland
FieldStateOption: Portugal
FieldStateOption: Romania
FieldStateOption: Slovakia
FieldStateOption: Slovenia
FieldStateOption: Spain
FieldStateOption: Sweden
---
FieldType: Text
FieldName: City Text Box
FieldValue:
FieldMaxLength: 40
---
FieldType: Text
FieldName: Postcode Text Box
FieldValue:
FieldMaxLength: 20
---
FieldType: Text
FieldName: Address 2 Text Box
FieldValue: adzazd
FieldMaxLength: 40
---
FieldType: Text
FieldName: House nr Text Box
FieldValue:
FieldMaxLength: 20
---
FieldType: Text
FieldName: Address 1 Text Box
FieldValue: azdad
FieldMaxLength: 40
---
FieldType: Text
FieldName: Family Name Text Box
FieldValue: azdzad
FieldMaxLength: 40
---
FieldType: Text
FieldName: Given Name Text Box
FieldValue: dzadazd
FieldMaxLength: 40

Build it

brew install poppler
make