Explore the API with Postman

This is an optional step. It will help you better visualize what the clients are doing.

Click here to skip this step.

Configure Postman

(if you did this when exploring v1, you can skip this configuration)

When Postman GETs hypermedia, you can click on the links to open a new request tab. Because the Event Buddy service has authentication, you must supply an Authorization: header for requests to be successful. It is a pain having to set this header for each request tab. Postman has a setting that makes this easier.

In the Postman menu: File->Settings->General, enable "Retain headers when clicking on links".

Now we can set the Authorization: header for our first GET request, and the header will follow with each link we click.

GET the root resource

In a request tab:

• select GET
• enter the url: http://localhost:2112
• click the request Headers and add this header (if it's not already there from last time):
  • Key:    Authorization
  • Value: Basic cm9vdDpwYXNzd29yZA==
• click Send

This will produce a JSON response (HAL actually), which will be different from the time we did this using Event Buddy v1:

{
    "_links": {
        "venues-service:logging": {
            "href": "http://192.168.1.94:2113/_logging",
            "title": "logging"
        },
        "venues-service:settings": {
            "href": "http://192.168.1.94:2113/_settings",
            "title": "_settings"
        },
        "venues": {
            "href": "http://192.168.1.94:2113/venues",
            "title": "venues"
        },
        "accounts-service:logging": {
            "href": "http://192.168.1.94:2116/_logging",
            "title": "logging"
        },
        "accounts-service:settings": {
            "href": "http://192.168.1.94:2116/_settings",
            "title": "_settings"
        },
        "accounts": {
            "href": "http://192.168.1.94:2116/accounts",
            "title": "accounts"
        },
        "registrations-service:logging": {
            "href": "http://192.168.1.94:2114/_logging",
            "title": "logging"
        },
        "registrations-service:settings": {
            "href": "http://192.168.1.94:2114/_settings",
            "title": "_settings"
        },
        "registrations": {
            "href": "http://192.168.1.94:2114/registrations",
            "title": "registrations"
        },
        "events-service:logging": {
            "href": "http://192.168.1.94:2115/_logging",
            "title": "logging"
        },
        "events-service:settings": {
            "href": "http://192.168.1.94:2115/_settings",
            "title": "_settings"
        },
        "events": {
            "href": "http://192.168.1.94:2115/events",
            "title": "events"
        },
        "self": {
            "href": "http://localhost:2112/",
            "title": "hypermea-gateway root"
        },
        "logging": {
            "href": "http://localhost:2112/_logging",
            "title": "logging"
        },
        "settings": {
            "href": "http://localhost:2112/_settings",
            "title": "_settings"
        },
        "gateway_registrations": {
            "href": "http://localhost:2112/gateway_registrations",
            "title": "gateway_registrations"
        },
        "curies": [
            ...
            ...
        ]
    },
    "_etag": "39d2a88aae49af7887255e753318c302"
}

As before, this is the root resource: no data, only links. It different from what we saw in v1, but all the link relations from v1 are here (along with a bunch of new ones we'll ignore, including the curies thing).

Follow the links

Hover over each of the href values. You will see Postman recognizes them as links.

This time, the value of href for the venues link is http://192.168.1.94:2113/venues (on my machine - your IP address will likely be different). Look at the value of href for events: its under a different domain!

And yet, when a client follows the links by looking up the label (i.e. link relation), the client doesn't notice or care about these differences.

Try it by clicking on the href value for venues. As before Postman opens a new tab to GET that URL. Click "Send" to see the venues related to the root resource. Even though venues are now served by a different component at a different location, the same operation continues to produce the same results.

In the first venue's _links, find the link labelled events. Click on that href value to GET the events related to that venue, again - exactly as we did before. Only the href values are different.

Feel free to explore as you see fit.