Ghostscript nodejs client use sample added

ghostscript-nodejs/README.md

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+# Use Ghostscript with Functions
+
+This sample shows how to use Ghostscript with firebase functions. Ghostscript is a tool which is used to perform operations on the PDF files.
+
+## Functions Code
+
+See file [functions/index.js](functions/index.js) for the code.
+
+The dependencies are listed in [functions/package.json](functions/package.json).

ghostscript-nodejs/firebase.json

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+{
+  "database": {
+    "rules": "database.rules.json"
+  },
+  "hosting": {
+    "public": "public"
+  }
+}

ghostscript-nodejs/functions/.eslintrc.json

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+{
+  "parserOptions": {
+    // Required for certain syntax usages
+    "ecmaVersion": 2017
+  },
+  "plugins": [
+    "promise"
+  ],
+  "extends": "eslint:recommended",
+  "rules": {
+    // Removed rule "disallow the use of console" from recommended eslint rules
+    "no-console": "off",
+
+    // Removed rule "disallow multiple spaces in regular expressions" from recommended eslint rules
+    "no-regex-spaces": "off",
+
+    // Removed rule "disallow the use of debugger" from recommended eslint rules
+    "no-debugger": "off",
+
+    // Removed rule "disallow unused variables" from recommended eslint rules
+    "no-unused-vars": "off",
+
+    // Removed rule "disallow mixed spaces and tabs for indentation" from recommended eslint rules
+    "no-mixed-spaces-and-tabs": "off",
+
+    // Removed rule "disallow the use of undeclared variables unless mentioned in /*global */ comments" from recommended eslint rules
+    "no-undef": "off",
+
+    // Warn against template literal placeholder syntax in regular strings
+    "no-template-curly-in-string": 1,
+
+    // Warn if return statements do not either always or never specify values
+    "consistent-return": 1,
+
+    // Warn if no return statements in callbacks of array methods
+    "array-callback-return": 1,
+
+    // Requre the use of === and !==
+    "eqeqeq": 2,
+
+    // Disallow the use of alert, confirm, and prompt
+    "no-alert": 2,
+
+    // Disallow the use of arguments.caller or arguments.callee
+    "no-caller": 2,
+
+    // Disallow null comparisons without type-checking operators
+    "no-eq-null": 2,
+
+    // Disallow the use of eval()
+    "no-eval": 2,
+
+    // Warn against extending native types
+    "no-extend-native": 1,
+
+    // Warn against unnecessary calls to .bind()
+    "no-extra-bind": 1,
+
+    // Warn against unnecessary labels    
+    "no-extra-label": 1,
+
+    // Disallow leading or trailing decimal points in numeric literals
+    "no-floating-decimal": 2,
+
+    // Warn against shorthand type conversions
+    "no-implicit-coercion": 1,
+
+    // Warn against function declarations and expressions inside loop statements
+    "no-loop-func": 1,
+
+    // Disallow new operators with the Function object
+    "no-new-func": 2,
+
+    // Warn against new operators with the String, Number, and Boolean objects
+    "no-new-wrappers": 1,
+
+    // Disallow throwing literals as exceptions
+    "no-throw-literal": 2,
+
+    // Require using Error objects as Promise rejection reasons
+    "prefer-promise-reject-errors": 2,
+
+    // Enforce “for” loop update clause moving the counter in the right direction
+    "for-direction": 2,
+
+    // Enforce return statements in getters
+    "getter-return": 2,
+
+    // Disallow await inside of loops
+    "no-await-in-loop": 2,
+
+    // Disallow comparing against -0
+    "no-compare-neg-zero": 2,
+
+    // Warn against catch clause parameters from shadowing variables in the outer scope
+    "no-catch-shadow": 1,
+
+    // Disallow identifiers from shadowing restricted names
+    "no-shadow-restricted-names": 2,
+
+    // Enforce return statements in callbacks of array methods
+    "callback-return": 2,
+
+    // Require error handling in callbacks
+    "handle-callback-err": 2,
+
+    // Warn against string concatenation with __dirname and __filename
+    "no-path-concat": 1,
+
+    // Prefer using arrow functions for callbacks
+    "prefer-arrow-callback": 1,
+
+    // Return inside each then() to create readable and reusable Promise chains.
+    "promise/always-return": 2,
+
+    //Enforces the use of catch() on un-returned promises
+    "promise/catch-or-return": 2,
+
+    // Warn against nested then() or catch() statements
+    "promise/no-nesting": 1
+  }
+}

ghostscript-nodejs/functions/index.js

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+/**
+ * Copyright 2016 Google Inc. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+'use strict';
+
+const functions = require('firebase-functions');
+const { Storage } = require('@google-cloud/storage');
+const gcs = new Storage();
+const spawn = require('child-process-promise').spawn;
+const path = require('path');
+const os = require('os');
+const fs = require('fs');
+var gs = require('gs');
+
+
+//This function triggers whenever any pdf is uploaded to the firebase storage
+//and attempts to generate
+
+exports.makePreviews = functions.storage.object().onFinalize(async (object, event) => {
+
+  //Checking for pdf files
+  if (!object.name.endsWith('.pdf')) return false;
+
+  const filePath = object.name;
+
+  //slicing name and path
+  const splitFileName = object.name.split(".");
+  const fileID = splitFileName[0].split("/")[1];
+
+  console.log("File ID -", fileID);
+
+  //creating temporary path strings for gcp file system
+  const fileName = path.basename(filePath);
+  const tempFilePath = path.join(os.tmpdir(), fileName);
+
+  const newName1 = path.basename(filePath, '.pdf') + '01.jpeg';
+  const tempNewPath1 = path.join(os.tmpdir(), newName1);
+
+  const newName2 = path.basename(filePath, '.pdf') + '02.jpeg';
+  const tempNewPath2 = path.join(os.tmpdir(), newName2);
+
+
+  //downloading file from firebase storage
+  const bucket = gcs.bucket(object.bucket);
+
+  return bucket.file(filePath).download({
+    destination: tempFilePath
+  }).then(async () => {
+    console.log('PDF downloaded locally to', tempFilePath);
+
+    //generating two preview JPEGS
+    await new Promise((resolve, reject) => {
+      gs()
+        .batch()
+        .option('-dFirstPage=1')
+        .option('-dLastPage=1')
+        .nopause()
+        .res(90)
+        .executablePath('gs')
+        .device('jpeg')
+        .output(tempNewPath1)
+        .input(tempFilePath)
+        .exec((err, stdout, stderr) => {
+          if (!err) {
+            console.log('gs executed w/o error');
+            console.log('stdout', stdout);
+            console.log('stderr', stderr);
+            resolve();
+          } else {
+            console.log('gs error:', err);
+            reject(err);
+          }
+        });
+    });
+
+    return new Promise((resolve, reject) => {
+      gs()
+        .batch()
+        .option('-dFirstPage=2')
+        .option('-dLastPage=2')
+        .nopause()
+        .res(90)
+        .executablePath('gs')
+        .device('jpeg')
+        .output(tempNewPath2)
+        .input(tempFilePath)
+        .exec((err, stdout, stderr) => {
+          if (!err) {
+            console.log('gs executed w/o error');
+            console.log('stdout', stdout);
+            console.log('stderr', stderr);
+            resolve();
+          } else {
+            console.log('gs error:', err);
+            reject(err);
+          }
+        });
+    });
+
+  }).then(async () => {
+    console.log('PNG created at', tempNewPath1 + 'and' + tempNewPath2);
+
+    //uploading the files back to firebase storage
+    await bucket.upload(tempNewPath1, {
+      destination: '/files/' + fileID + '/' + fileID + '-01.jpeg'
+    });
+
+    return bucket.upload(tempNewPath2, {
+      destination: '/files/' + fileID + '/' + fileID + '-02.jpeg'
+    });
+
+
+
+  }).then(() => {
+    //once the files have been uploaded delete the local temporary 
+    //files to free up disk space.
+    fs.unlinkSync(tempNewPath1);
+    fs.unlinkSync(tempNewPath2);
+    return fs.unlinkSync(tempFilePath);
+  }).catch((err) => {
+    console.log('exception:', err);
+    return err;
+  });
+
+});

ghostscript-nodejs/functions/lambda-ghostscript/README.md

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+# lambda-ghostscript
+
+This repository contains a compiled version of Ghostscript which works with Amazon Web Services(AWS) Lambda.
+
+These binaries are based on Ghostscript 9.20.
+
+AWS Lambda is using an old version of Ghostscript which causes many issues. Lambda has the ability to use local libraries which can be packed inside the function archive, this repository can save you some time.
+
+You should include the files inside your project and use a Ghostscript Node js package to use it.
+
+This is an npm package to call Ghostscript functions:
+
+https://github.com/sina-masnadi/node-gs
+
+After copying the compiled Ghostscript files to your project and adding the npm package, you can use the executablePath('path to ghostscript') function to point the package to the compiled Ghostscript files that you added earlier.

ghostscript-nodejs/functions/lambda-ghostscript/bin/dvipdf

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+#!/bin/sh
+# Convert DVI to PDF.
+#
+# Please contact Andrew Ford <A.Ford@ford-mason.co.uk> with any questions
+# about this file.
+#
+# Based on ps2pdf
+
+# This definition is changed on install to match the
+# executable name set in the makefile
+GS_EXECUTABLE=gs
+
+
+OPTIONS=""
+DVIPSOPTIONS=""
+while true
+do
+	case "$1" in
+	-R*) DVIPSOPTIONS="$DVIPSOPTIONS $1";;
+	-?*) OPTIONS="$OPTIONS $1" ;;
+	*)  break ;;
+	esac
+	shift
+done
+
+if [ $# -lt 1 -o $# -gt 2 ]; then
+	echo "Usage: `basename \"$0\"` [options...] input.dvi [output.pdf]" 1>&2
+	exit 1
+fi
+
+infile=$1;
+
+if [ $# -eq 1 ]
+then
+	case "${infile}" in
+	  *.dvi)	base=`basename "${infile}" .dvi` ;;
+	  *)		base=`basename "${infile}"` ;;
+	esac
+	outfile="${base}".pdf
+else
+	outfile=$2
+fi
+
+# We have to include the options twice because -I only takes effect if it
+# appears before other options.
+exec dvips -Ppdf $DVIPSOPTIONS -q -f "$infile" | $GS_EXECUTABLE $OPTIONS -q -P- -dSAFER -dNOPAUSE -dBATCH -sDEVICE=pdfwrite -sstdout=%stderr -sOutputFile="$outfile" $OPTIONS -c .setpdfwrite -

ghostscript-nodejs/functions/lambda-ghostscript/bin/eps2eps

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+#!/bin/sh
+# "Distill" Encapsulated PostScript.
+
+# This definition is changed on install to match the
+# executable name set in the makefile
+GS_EXECUTABLE=gs
+gs="`dirname \"$0\"`/$GS_EXECUTABLE"
+if test ! -x "$gs"; then
+	gs="$GS_EXECUTABLE"
+fi
+GS_EXECUTABLE="$gs"
+
+OPTIONS="-dDEVICEWIDTH=250000 -dDEVICEHEIGHT=250000"
+while true
+do
+	case "$1" in
+	-?*) OPTIONS="$OPTIONS $1" ;;
+	*)  break ;;
+	esac
+	shift
+done
+
+if [ $# -ne 2 ]; then
+	echo "Usage: `basename \"$0\"` ...switches... input.eps output.eps" 1>&2
+	exit 1
+fi
+
+exec "$GS_EXECUTABLE" -q -sDEVICE=eps2write -sstdout=%stderr "-sOutputFile=$2" -dNOPAUSE -dBATCH -P- -dSAFER $OPTIONS "$1"

ghostscript-nodejs/functions/lambda-ghostscript/bin/font2c

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+#!/bin/sh
+
+# This definition is changed on install to match the
+# executable name set in the makefile
+GS_EXECUTABLE=gs
+gs="`dirname \"$0\"`/$GS_EXECUTABLE"
+if test ! -x "$gs"; then
+	gs="$GS_EXECUTABLE"
+fi
+GS_EXECUTABLE="$gs"
+
+exec "$GS_EXECUTABLE" -q -P- -dSAFER -dNODISPLAY -dWRITESYSTEMDICT -- font2c.ps "$@"

ghostscript-nodejs/functions/lambda-ghostscript/bin/gsbj

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+#!/bin/sh
+
+# This definition is changed on install to match the
+# executable name set in the makefile
+GS_EXECUTABLE=gs
+gs="`dirname \"$0\"`/$GS_EXECUTABLE"
+if test ! -x "$gs"; then
+	gs="$GS_EXECUTABLE"
+fi
+GS_EXECUTABLE="$gs"
+
+exec "$GS_EXECUTABLE" -q -sDEVICE=bj10e -r180 -P- -dSAFER -dNOPAUSE -sPROGNAME=$0 -- gslp.ps --heading-center "`date`" "$@"