README

The presentation service is a thin wrapper around redis for doing joins via in place string replacement on request.

How does it work?

The presentation service is a node web-server that requires a redis instance as a backing database (or that runs off process memory for testing purposes). It also come bundles with a node js based javascript sdk for making requests to a presentation service instance.

How do I use it?

The web-server

The server is started from server.js. There is an example configuration of the web-server in config/default.js, which is imported using node-config.

Running the web-server locally

First, build the presentation service docker image using

docker build .

which will output the #presentationServiceDockerHash

In order to actually run the presentation service a redis instance must already be running. To run a local instance of redis in a docker container that will work with the example config, run the following commands to set up a redis container linked to a presentation service instance:

docker run --name redis -d redis
docker run --name presentation-service --link redis:redis -d #presentationServiceDockerHash

The sdk

After installing with npm install -s presentation-service, use

var ps = require('presentation-service')('<web-server-url>');

where <web-server-url> is the url of a hosted presentation-service, this will expose a number of functions

put: (key, value, cb) => void - Sets value at key
del: (key, cb) => void - deletes the value at key
add: (key, score, value, cb) => void - adds value to the list at key
del: (key, cb) => void - deletes the value at key
rem: (key, value, cb) => void - removes the value from the list at key
get: (key, cb) => void - gets the value at key, hydating any placeholders. If the value is a list it will return it in the form [<val1>,<val1>,..] where <val1> etc are the hydrated values in the list.

keys

The keys of that are used in the presentation-service must be prefixed by an api-version else as that determines what code is used to process it e.g. /v1/cat it processes with api version v1.

The general format of a place-holder is ${<resource>} where <resource> is normally just the key for the value, however a resource can have the following format <key>[,<prop_1>,<prop_2>..][;<default>] Here square brackets denote optional parameters and angle brackets denote parameters. A resource of this form will output the value of the <key>[,<prop_1>,<prop_2>..] if it is successfully retrieved otherwise it returns <default> if it is given or an error message. Furthermore if the value at <key> is JSON then what is returned is the value found when you pick the prop_1 field from that json and the prop_2 from that and so on. for example given that { foo: { bar: "hoot" } } is saved at '/v1/key', then /v1/key,foo,bar will return "hoot" and /v1/key,foo,car;woot will return "woot"

To query a range of items from a list, append the url with [<min>|<max>]^<limit>. For example /v1/nationals-live/6679834[1|2]^1 All parameters are optional.

#Contributors Dayo Adeyemi

Deploying to presentation service

publish latest version to npm docker build -t trinitymirror/presentation-service:version . docker push trinitymirror/presentation-service:version update the presentation version in /live-centre/live-centre-launcher/config/default.json deploy the live-centre env bitbucket trigger