PDF thumbnail lambda

This package contains functionality to make a PNG thumbnail of the first page of a pdf file, using Ghostscript. There is also functionality to work with S3 and S3 events.

Installation

Ghostscript is required for the runtime, and Jasmine and Jshint are needed for the test. The other node dependencies can be installed with:

npm install

make-pdf-thumbnail

This stand-alone module provides functionality to make a thumbnail of the first page of a pdf.

Example usage

The function expects a buffer containing pdf data, the device resolution (72 is a good setting), and a callback. The callback has as second argument the output buffer containing PNG data. No temporary files are used.

var makePdfThumbnail = require('./make-pdf-thumbnail');
var fs = require('fs');
makePdfThumbnail(inputBuffer, resolution, function(err, buffer) {
  if (err) {
    console.log('pdf error', err);
  }

});

lambda-pdf-thumbnail

This module provides functionality to make a pdf thumbnail, where the data is read and written to S3 buckets. In addition, a S3 event handler is provided. The bucket the thumbnail is saved to can be specified, either by a bucket name, or by a dynamodb table that has an input-bucket to output-bucket mapping.

Example usage

The generateThumbnail function expects as arguments: an AWS.S3 object, device resolution, and the input/output bucket and key.

var lambdaPdfThumbnail = require('./lambda-pdf-thumbnail');
lambdaPdfThumbnail.generateThumbnail(s3, 72, 'input-bucket', 'input.pdf',
                                     'output-bucket', 'output.png', function(err) {
                                     if (err) {
                                       console.log('generate thumbnail failed');
                                       return;
                                     }
                                     console.log('generate thumbnail succeeded');
});

To use the S3EventHandler, either the table name , or the output bucket must be specified. In addition, the region property is required to stop AWS.DyanomDB from complaining. The following example demonstrates how to make a handler that looks for DestinationBucket in the table TestTable by searching with hash SourceBucket.

var S3EventHandler = require('./lambda-pdf-thumbnail').S3EventHandler;
var s3EventHandler = new S3EventHandler({
  region:'eu-west-1',
  tableName: 'TestTable',
  s3: s3,
  dynamodb: dynamodb,

  // Optional properties with their default values
  sourceHash: 'SourceBucket',
  destinationHash: 'DestinationBucket',
  resolution: 72
});

// for some reason it needs to be wrapped into a function
exports.handler = function(event, context){
  'use strict';
  s3EventHandler.handler(event, context); 
};

A fixed output bucket can also be specified.

var S3EventHandler = require('./lambda-pdf-thumbnail').S3EventHandler;
var s3EventHandler = new S3EventHandler({
  region:'eu-west-1',
  outputBucketName: 'output-bucket'
  s3: s3,
  resolution: 72
});

// for some reason it needs to be wrapped into a function
exports.handler = function(event, context){
  'use strict';
  s3EventHandler.handler(event, context); 
};