Add a cover page to one or more PDF documents using curl and https://documentalchemy.com/

add-cover.sh

#!/bin/bash
# Adds a cover page to one or more PDF documents.

# USAGE: add-cover.sh <COVER-PAGE> <FILES>
#
# EXAMPLE: add-cover.sh cover.pdf doc/*.pdf


# This is your DocumentAlchemy API key.  It may be set via the
# environment variable named `DA_API_KEY`.
# (See <https://documentalchemy.com/> to get one of your own.)
API_KEY=${DA_API_KEY:-"403l1zh3dkbakyb9"}

# This is a flag that can prevent this script from `echo`ing
# unnecessary information.  It can be set via the environment
# variable `QUIET`. A clever person could make this into a
# command line parameter like `-q`.
QUIET=${QUIET:-FALSE}

# Note that you can set environment variables on a per-invocation
# basis by prefixing NAME=VALUE before the command.  For example:
#   API_KEY=my-key QUIET=true doc2docx *.doc

# EXIT_CODE tracks the number of files we couldn't extract from.
EXIT_CODE=0


# The first argument contains the cover page.
COVER_PAGE=$1
# The rest will be filenames, so "shift" the first argument away and process the rest.
shift;

# Loop over the command line parameters....
for pdf in "$@"; do
  # ...testing that is is an accessible file...
  if ! [ -s "$pdf" ]; then
    $QUIET || echo "WARNING: File '$pdf' was not found and will be ignored."
    EXIT_CODE=$((EXIT_CODE+1))
  else
    # ...if so, POST to DocumentAlchemy to join the documents
    outfile="`dirname "$pdf"`/covered-`basename "$pdf"`"
    $QUIET || echo "Adding cover page '$COVER_PAGE' to '$pdf'...";
    response=$(curl --silent \
                    --write-out %{http_code} -H "Authorization: da.key=$API_KEY" \
                    -X POST \
                    -F "document=@$COVER_PAGE" \
                    -F "document=@$pdf" \
                    https://documentalchemy.com/api/v1/documents/-/rendition/combined.pdf \
                    -o "$outfile")
    # ...and report success or failure.
    if ! [ "$response" -eq "200" ]; then
      $QUIET || echo "WARNING: Expected a 200 response for file '$pdf', found $response instead.";
      EXIT_CODE=$((EXIT_CODE+1))
    else
      $QUIET || echo "...OK. File '$outfile' created."
    fi
  fi
done

# Exit with the number of documents that could not be joined.
exit $EXIT_CODE

See "5 Things You Can Do With DocumentAlchemy: Add a cover page to a PDF document." for context.

Also see a variation on this script using the DocumentAlchemy command-line interface.