'use strict';
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var url = require('url');
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exports = module.exports = function historyApiFallback(options) {
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options = options || {};
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var logger = getLogger(options);
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return function(req, res, next) {
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var headers = req.headers;
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if (req.method !== 'GET') {
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logger(
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'Not rewriting',
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req.method,
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req.url,
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'because the method is not GET.'
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);
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return next();
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} else if (!headers || typeof headers.accept !== 'string') {
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logger(
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'Not rewriting',
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req.method,
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req.url,
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'because the client did not send an HTTP accept header.'
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);
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return next();
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} else if (headers.accept.indexOf('application/json') === 0) {
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logger(
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'Not rewriting',
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req.method,
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req.url,
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'because the client prefers JSON.'
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);
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return next();
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} else if (!acceptsHtml(headers.accept, options)) {
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logger(
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'Not rewriting',
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req.method,
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req.url,
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'because the client does not accept HTML.'
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);
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return next();
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}
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var parsedUrl = url.parse(req.url);
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var rewriteTarget;
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options.rewrites = options.rewrites || [];
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for (var i = 0; i < options.rewrites.length; i++) {
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var rewrite = options.rewrites[i];
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var match = parsedUrl.pathname.match(rewrite.from);
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if (match !== null) {
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rewriteTarget = evaluateRewriteRule(parsedUrl, match, rewrite.to, req);
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if(rewriteTarget.charAt(0) !== '/') {
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logger(
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'We recommend using an absolute path for the rewrite target.',
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'Received a non-absolute rewrite target',
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rewriteTarget,
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'for URL',
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req.url
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);
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}
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logger('Rewriting', req.method, req.url, 'to', rewriteTarget);
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req.url = rewriteTarget;
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return next();
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}
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}
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var pathname = parsedUrl.pathname;
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if (pathname.lastIndexOf('.') > pathname.lastIndexOf('/') &&
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options.disableDotRule !== true) {
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logger(
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'Not rewriting',
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req.method,
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req.url,
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'because the path includes a dot (.) character.'
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);
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return next();
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}
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rewriteTarget = options.index || '/index.html';
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logger('Rewriting', req.method, req.url, 'to', rewriteTarget);
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req.url = rewriteTarget;
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next();
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};
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};
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function evaluateRewriteRule(parsedUrl, match, rule, req) {
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if (typeof rule === 'string') {
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return rule;
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} else if (typeof rule !== 'function') {
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throw new Error('Rewrite rule can only be of type string or function.');
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}
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return rule({
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parsedUrl: parsedUrl,
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match: match,
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request: req
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});
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}
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function acceptsHtml(header, options) {
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options.htmlAcceptHeaders = options.htmlAcceptHeaders || ['text/html', '*/*'];
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for (var i = 0; i < options.htmlAcceptHeaders.length; i++) {
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if (header.indexOf(options.htmlAcceptHeaders[i]) !== -1) {
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return true;
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}
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}
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return false;
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}
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function getLogger(options) {
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if (options && options.logger) {
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return options.logger;
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} else if (options && options.verbose) {
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return console.log.bind(console);
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}
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return function(){};
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}
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