web-resource-inliner/src/util.js

Inlines img, script and link tags into the same file.

"use strict";

var path = require( "path" );
var url = require( "url" );
var datauri = require( "datauri" );
var fs = require( "fs" );
var request = require( "request" );
var chalk = require( "chalk" );

var util = {};

module.exports = util;

util.defaults = {
    images: 8,
    svgs: 8,
    scripts: true,
    links: true,
    strict: false,
    relativeTo: "",
    rebaseRelativeTo: "",
    inlineAttribute: "data-inline",
    fileContent: "",
    requestTransform: undefined,
    scriptTransform: undefined,
    linkTransform: undefined
};

util.attrValueExpression = "(=[\"']([^\"']+?)[\"'])?";

/**
 * Escape special regex characters of a particular string
 *
 * @example
 * "http://www.test.com" --> "http:\/\/www\.test\.com"
 *
 * @param  {String} str - string to escape
 * @return {String} string with special characters escaped
 */
util.escapeSpecialChars = function( str )
{
    return str.replace( /(\/|\.|\$|\^|\{|\[|\(|\||\)|\*|\+|\?|\\)/gm, "\\$1" );
};

util.isRemotePath = function( url )
{
    return /^'?https?:\/\/|^\/\//.test( url );
};

util.isBase64Path = function( url )
{
    return /^'?data.*base64/.test( url );
};

util.getAttrs = function( tagMarkup, settings )
{
    var tag = tagMarkup.match( /^<[^\W>]*/ );
    if( tag )
    {
        tag = tag[ 0 ];
        var attrs = tagMarkup
            .replace( /(<[\s\S]*?(?=\>))([\s\S]*?(?=\<\/))(<\/[\w\W]>)?/gm, "$1>$3" )
            .replace( /^<[^\s>]*/, "" )
            .replace( /\/?>/, "" )
            .replace( />?\s?<\/[^>]*>$/, "" )
            .replace( new RegExp( settings.inlineAttribute + "-ignore" + util.attrValueExpression, "gi" ), "" )
            .replace( new RegExp( settings.inlineAttribute + util.attrValueExpression, "gi" ), "" );

        if( tag === "<script" || tag === "<img" )
        {
            return attrs.replace( /(src|language|type)=["'][^"']*["']/gi, "" ).trim();
        }
        else if( tag === "<link" )
        {
            return attrs.replace( /(href|rel)=["'][^"']*["']/g, "" ).trim();
        }
    }
};

function getRemote( uri, settings, callback, toDataUri )
{
    if( /^\/\//.test( uri ) )
    {
        uri = "https:" + uri;
    }

    var requestOptions = {
        uri: uri,
        encoding: toDataUri ? "binary" : "",
        gzip: true
    };

    if( typeof settings.requestTransform === "function" )
    {
        var transformedOptions = settings.requestTransform( requestOptions );
        if( transformedOptions === false )
        {
            return callback();
        }
        if( transformedOptions === undefined )
        {
            return callback( new Error( uri + " requestTransform returned `undefined`" ) );
        }
        requestOptions = transformedOptions || requestOptions;
    }

    request(
        requestOptions,
        function( err, response, body )
        {
            if( err )
            {
                return callback( err );
            }
            else if( response.statusCode !== 200 )
            {
                return callback( new Error( uri + " returned http " + response.statusCode ) );
            }

            if( toDataUri )
            {
                var b64 = new Buffer( body.toString(), "binary" ).toString( "base64" );
                var datauriContent = "data:" + response.headers[ "content-type" ] + ";base64," + b64;
                return callback( null, datauriContent );
            }
            else
            {
                return callback( null, body );
            }
        } );
}

util.getInlineFilePath = function( src, relativeTo )
{
    src = src.replace( /^\//, "" );
    return path.resolve( relativeTo, src ).replace( /\?.*$/, "" );
};

util.getInlineFileContents = function( src, relativeTo )
{
    return fs.readFileSync( util.getInlineFilePath( src, relativeTo ) );
};

util.getTextReplacement = function( src, settings, callback )
{
    if( util.isRemotePath( settings.relativeTo ) || util.isRemotePath( src ) )
    {
        getRemote( url.resolve( settings.relativeTo, src ), settings, callback );
    }
    else if( util.isRemotePath( src ) )
    {
        getRemote( src, settings, callback );
    }
    else
    {
        try
        {
            var replacement = util.getInlineFileContents( src, settings.relativeTo );
        }
        catch( err )
        {
            return callback( err );
        }
        return callback( null, replacement );
    }
};

util.getFileReplacement = function( src, settings, callback )
{
    if( !src || util.srcIsCid( src ) )
    {
        callback( null );
    }
    else if( util.isRemotePath( settings.relativeTo ) )
    {
        getRemote( url.resolve( settings.relativeTo, src ), settings, callback, true );
    }
    else if( util.isRemotePath( src ) )
    {
        getRemote( src, settings, callback, true );
    }
    else
    {
        var result = ( new datauri( util.getInlineFilePath( src, settings.relativeTo ) ) ).content;
        callback( result === undefined ? new Error( "Local file not found" ) : null, result );
    }
};

util.srcIsCid = function( src )
{
    return src.match( /^cid:/ );
};

util.handleReplaceErr = function( err, src, strict, callback )
{
    if( strict )
    {
        return callback( err );
    }
    else
    {
        console.warn( chalk.yellow( "Not found, skipping: " + src ) );
        return callback( null );
    }
};