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Fill out PDF forms with pdftk.


You'll need a working pdftk binary. Either get a binary package from and install it, or run apt-get install pdftk if you're on Debian or similar.

After that, add pdf-forms to your Gemfile or manually install the gem. Nothing unusual here.


FDF/XFdf creation

require 'pdf_forms'
fdf = :key => 'value', :other_key => 'other value'
# use to_pdf_data if you just want the fdf data, without writing it to a file
puts fdf.to_pdf_data
# write fdf file
fdf.save_to 'path/to/file.fdf'

To generate XFDF instead of FDF instantiate PdfForms::XFdf instead of PdfForms::Fdf

Query form fields and fill out PDF forms with pdftk

require 'pdf_forms'

# adjust the pdftk path to suit your pdftk installation
# add :data_format => 'XFdf' option to generate XFDF instead of FDF when
# filling a form (XFDF is supposed to have better support for non-western
# encodings)
# add :data_format => 'FdfHex' option to generate FDF with values passed in
# UTF16 hexadecimal format (Hexadecimal format has also proven more reliable
# for passing latin accented characters to pdftk)
# add :utf8_fields => true in order to get UTF8 encoded field metadata (this
# will use dump_data_fields_utf8 instead of dump_data_fields in the call to
# pdftk)
pdftk ='/usr/local/bin/pdftk')

# find out the field names that are present in form.pdf
pdftk.get_field_names 'path/to/form.pdf'

# take form.pdf, set the 'foo' field to 'bar' and save the document to myform.pdf
pdftk.fill_form '/path/to/form.pdf', 'myform.pdf', :foo => 'bar'

# optionally, add the :flatten option to prevent editing of a filled out form.
# Other supported options are :drop_xfa and :drop_xmp.
pdftk.fill_form '/path/to/form.pdf', 'myform.pdf', {:foo => 'bar'}, :flatten => true

# to enable PDF encryption, pass encrypt: true. By default, a random 'owner
# password' will be used, but you can also set one with the :encrypt_pw option.
pdftk.fill_form '/path/to/form.pdf', 'myform.pdf', {foo: 'bar'}, encrypt: true, encrypt_options: 'allow printing'

# you can also protect the PDF even from opening by specifying an additional user_pw option:
pdftk.fill_form '/path/to/form.pdf', 'myform.pdf', {foo: 'bar'}, encrypt: true, encrypt_options: 'user_pw secret'

Any options shown above can also be set when initializing the PdfForms instance. In this case, options given to fill_form will override the global options.

Field names with HTML entities

In case your form's field names contain HTML entities (like Straße Hausnummer), make sure you unescape those before using them, i.e. CGI.unescapeHTML(name). Thanks to @phoet for figuring this out in #65.

Non-ASCII Characters (UTF8 etc) are not displayed in the filled out PDF

First, check if the field value has been stored properly in the output PDF using pdftk output.pdf dump_data_fields_utf8.

If it has been stored but is not rendered, your input PDF lacks the proper font for your kind of characters. Re-create it and embed any necessary fonts. If the value has not been stored, there is a problem with filling out the form, either on your side, of with this gem.

Also see UTF-8 chars are not displayed in the filled PDF

Prior Art

The FDF generation part is a straight port of Steffen Schwigon's PDF::FDF::Simple perl module. Didn't port the FDF parsing, though ;-)


Created by Jens Kraemer and licensed under the MIT License.

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