first commit

Author: ToMGitHubN

.gitignore

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+/node_modules
+# setting.yaml

README.md

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+# gcs-basic-auth

app.yaml

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+runtime: nodejs10
+env: standard
+instance_class: F1
+includes:
+- setting.yaml

index.js

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+'use strict';
+
+if(process.env.STACKDRIVER_DEBUGGER === 'true'){
+  require('@google-cloud/debug-agent').start();
+}
+
+const request = require('request');
+var url = require('url');
+
+const express = require('express');
+const app = express();
+
+const basicAuthConnect = require('basic-auth-connect');
+
+
+const {Storage} = require('@google-cloud/storage');
+const storage = new Storage();
+
+
+// basic auth setting
+const basicAuth = basicAuthConnect(process.env.BASIC_AUTH_NAME, process.env.BASIC_AUTH_PASSWORD);
+
+// bucket
+const bucket = storage.bucket(process.env.BUCKET_NAME);
+
+// Google Cloud Storage generateSignedUrl Life time
+const GCS_URL_LIFETIME = parseInt(process.env.GCS_URL_LIFETIME);
+
+//transfer option
+const TRANSFER_MODE = process.env.TRANSFER_MODE;
+const ALLOW_DIRECT_LIST = JSON.parse(process.env.ALLOW_DIRECT_LIST);
+const ALLOW_REDIRECT_LIST = JSON.parse(process.env.ALLOW_REDIRECT_LIST);
+
+// default page
+const DEFAULT_HTML = process.env.DEFAULT_PAGE;
+// 404 page
+const NOT_FOUND_HTML = process.env.NOT_FOUND_PAGE;
+
+
+
+
+// Constants
+const REDIRECT = 'REDIRECT';
+const SIGNEDURL = 'SIGNEDURL';
+const FILE_NOT_FOUND = 'FILE_NOT_FOUND';
+
+
+
+/**
+ * file exists check
+ * 
+ * return bool true=file exist
+ */
+async function checkFileExists(filename) {
+
+  const [exists] = await bucket
+    .file(filename)
+    .exists()
+    .catch(err => {
+      throw err;
+    });
+    
+  
+  return exists;
+}
+
+
+/**
+ * Google Cloud Storage Generate Signerate URL
+ * 
+ * @param {string} filepath 
+ * @return {string} Signerate URL
+ */
+async function generateSignedUrl(filepath) {
+
+  const options = {
+    action: 'read',
+    expires: Date.now() + GCS_URL_LIFETIME,
+  };
+  
+  // Get a signed URL for the file
+  const [url] = await bucket
+    .file(filepath)
+    .getSignedUrl(options);
+
+  
+  return url;
+}
+
+
+async function fileSearch(url_parse) {
+
+  let  path_name = url_parse.pathname;
+
+  if(path_name.slice(-1) === '/'){
+  	path_name = path_name.slice(0, -1);// remove '/'
+  }
+
+ 
+  let is_file = false;//file find flg
+  
+  if(path_name !== ''){
+  	is_file = await checkFileExists(path_name);//file check
+  }
+
+  
+  if( is_file === false ){//file not found
+    
+
+  	if( await checkFileExists( `${path_name}/${DEFAULT_HTML}`) ){//check defalut html
+  	  is_file = true;
+  	  path_name = `${path_name}/${DEFAULT_HTML}`;
+  	}
+
+  	
+  	if(is_file === false){//defalut html not found
+  		
+  		if( await checkFileExists(`/${NOT_FOUND_HTML}`) ){// check 404 html
+  			is_file = true;
+  	  	    path_name = `/${NOT_FOUND_HTML}`;
+  		}else{
+  			return [FILE_NOT_FOUND, ''];
+  		}
+  	}
+  }
+
+  
+  let file_signed_url = await generateSignedUrl(path_name);
+  
+  if(TRANSFER_MODE === 'ALL_DIRECT'){
+
+    return [SIGNEDURL, file_signed_url];
+
+  }else{
+    
+    const file_split_ext = path_name.split('.');
+    if(file_split_ext.length > 0 ){
+      const file_ext = file_split_ext[file_split_ext.length-1].toLowerCase();
+      
+      if(TRANSFER_MODE === 'ALLOW_DIRECT' && ALLOW_DIRECT_LIST.indexOf(file_ext) >= 0){
+
+        return [SIGNEDURL, file_signed_url];//target transfer files
+
+      }else if(TRANSFER_MODE === 'ALLOW_REDIRECT' && ALLOW_REDIRECT_LIST.indexOf(file_ext) === -1){
+
+        return [SIGNEDURL, file_signed_url];//target transfer files
+      }
+    }
+  }
+  
+  
+  
+  //redirect path
+  if(url_parse.query){//check get param
+  	file_signed_url = file_signed_url + '?' + url_parse.query;
+  }
+  
+  return [REDIRECT, file_signed_url];
+}
+
+
+
+
+
+/**
+ * helath check
+ */
+app.get('/_ah/start', (req, res) => {
+	
+	res.send('I am alive.');
+	
+});
+
+
+
+/**
+ * main url listener
+ */
+app.get('/*', basicAuth, (req, res) => {
+  	
+  const url_parse = url.parse(req.url);
+  	
+  
+  fileSearch(url_parse).then(result => {
+  	
+	const [result_status, result_url]  = result;
+	
+	if(result_status === REDIRECT){
+		
+		res.redirect(result_url);
+		
+	}else if(result_status === SIGNEDURL){
+		
+		const proxyRequestHeaders = Object.assign({}, req.headers);
+	    for(let key of ['host', 'authorization', 'cookie']){
+	    	if(key in proxyRequestHeaders){
+	    		delete proxyRequestHeaders[key];
+	    	}
+	    }
+
+	    request({
+	      url: result_url,
+	      method: req.method,
+	      headers: proxyRequestHeaders,
+	    }).pipe(res);
+	    
+	}else if(result_status === FILE_NOT_FOUND){
+		
+		res.status(404).end('404 Not Found');
+	}else{
+		//It will never reach this code
+		res.status(500).end('500 Internal Server Error');
+	}
+	
+  });
+
+ 	
+});
+
+
+/**
+ * server start
+ */
+const server = app.listen(8080);