#What's TeenyURL?

TeenyURL is a very cool web application. It turns a very long URL into a much shorter one. Then you use the shorter one in your blog post and email. When someone click it, teenyURL application can help you redirect to the long one.

#Introduction of techniques

Teenyurl is written with node.js and express framework. It can run either on Platform such as VMware Tempest or Cloud Foundry, or in your local box. It uses PostgreSql preferably to store persistent data, and Redis as cache (optional). But the service binding logic is well-designed so you can easily bind it to other services such as mongodb, mysql etc.

Node.js is a server-side software system designed for writing scalable Internet applications, notably web servers. The teenyURL is a simple application. So it uses the node.js to implement the backend services which access the PostgreSql database and Redis cache server and exposes several RESTful APIs.

Express: is a minimal and flexible node.js web application framework, providing a robust set of features for building single and multi-page, and hybrid web applications.

PostgreSql is used to act as the RDMS, to persist the URL mapping data.

Redis is used to act as the high speed cache server. When user access the shorter URL, we can get the mapped long URL in redis very quickly.

For the frontend, the teenyURL is a typical one page application. It uses bootstrap css library to style the page and jquery ui timepicker addon.

#Run app on Tempest or Cloud Foundry

App Folder contains code for the web app. File manifest.yml in this folder already contains the info needed so you can directly push the app to Tempest/Cloud Foundry.

Note: If you test on run.pivotal.io, the Marketplace services for Postgres (ElephantSQL) and MySQL (ClearDB) use different attributes. If you push with ClearDB MySQL as shown in the manifest.yml it should work with a simple set of steps.

git clone https://github.com/vchs/heroapp-TeenyURL.git
cd heroapp-TeenyURL
cf push

If you want to push with ElephantSQL, please modify the service section in the manifest.yml as below before proceed with the above steps:

services:
  teenyurl-postgres-prod:
    label: elephantsql
    provider: elephantsql
    version: n/a
    plan: turtle

You can always customize the manifest such as binding services with different names. We recommend you change service name by adding suffix, such as add -qa for test app. In this way, new names still contain the earlier prefix, on which our code relies to bind the service. For example, for PostgreSql service, service names should be prefixed with 'teenyurl-postgres'.

##Bind to Tempest or CF services

Tempest or Cloud Foundry provide the environment variable for node.js application to bind the server port and services(PostgreSql or Redis) configration.

The environment variables are PORT and VCAP_SERVICES. You can take a look how we parse the variables in the app.js and lib/ServiceBinding.js.

#Run app in your local box

##Backend Service Setup

To use redis as cache, you need start a redis server

redis-server

Start your postgresql server and create a database 'teenyurl'. We assume your postgresql process is running under account 'postgres'.

createdb -U postgres teenyurl

Current postgres adapter doesn't support unix socket. It uses TCP right now. This works the same as on Tempest environment. For local testing, if you want to use 'postgres' as username without providing password, please edit pg_hba.conf and add the following line:

host all postgres 127.0.0.1/32 trust

##Environment setup for the app or test

To use services such as Redis/PostgreSql, an environment variable VCAP_SERVICES need be set before starting the app or running the functional test. We provide several shell script files you can choose to set the intended environment variable.

source ./env/local-postgres.sh

Note: we assume your postgresql process runs under account 'postgres'. If not, please update the preconfigured 'username' within ./local-postgres.sh accordingly.

You can also specify the environment variable the time running the app or test.

VCAP_SERVICES='{ "redis": [{"name": "teenyurl-redis-cache-prod", "credentials": { "host": "YOUR_REDIS_HOST", "port": YOUR_REDIS_PORT, "password": "YOUR_REDIS_PASSWORD" } }] , "postgres": [{"name" : "teenyurl-postgres-prod", "credentials" : { "database" : "teenyurl", "username" : "postgres" }}] }' COMMAND

Please be noted: VCAP_SERVICES is an hash in JSON format. One item within the hash specifies one service.

##How to run app After setting environment variables, go to app folder, and type npm install for the first time

Launch the web app.

npm start

or

node app

##How to run test

Go to test folder, and type npm install for the first time.

###Unit Tests

npm test

By default, it will run all unit tests, using mocha.

###Functional Tests

By providing different VCAP_SERVICES value, you can decide whether to run functional tests for certain components. Take a look at helpers.js, and uses when(condition).describe(...) to enable a certain set of tests conditionally, just as we did in file SqlDataAccessor-func-test.js.

For example, to test only functional testcases for RedisCache but skip those for PostgreSQL, set environment variable VCAP_SERVICES to be

VCAP_SERVICES='{ "redis": [{"name": "teenyurl-redis-cache", "credentials": { "host": "YOUR_REDIS_HOST", "port": YOUR_REDIS_PORT, "password": "YOUR_REDIS_PASSWORD" } }] }' ./test.sh

You can also source files from env folder.