We stated before that Python's main aims are simplicity and code readability; unfortunately, this is not always the case. Interacting with REST using standard Python libraries may be painful and very verbose. Luckily, there is an open source project that solves this problem. The project produced a library called Requests and I have to say, it is a really appropriate name.

Let's install it!

You just installed the Requests library as a site package inside your Python installation. Furthermore, by asking for the license page on the GeoServer site, you also had your first taste of its power and simplicity. You can now use it inside any Python program, leveraging on its powerful objects to interact with the HTTP protocol.

In this recipe, you learned how to manage workspaces and namespaces. In GeoServer, a workspace is a logical object that you can use to group together data stores, feature types, coverages, and styles.

What's the difference between a workspace and a namespace? You first queried GeoServer for the NaturalEarth workspace and obtained its properties, which is basically a name:

    <name>NaturalEarth</name>

A namespace associated with a workspace that is in the form of a Uniform Resource Identifier (URI) and typically a URL always exists. Although you can insert any URL, it is usually a good choice to select something that is associated with your project.

Workspaces and namespace are very similar and, in fact, you created both by calling the namespace operation, perhaps with an added trailing identifier indicating the workspace.

The GeoServer REST interface exposes resources for each one of them; there are two resources that you can use to access these elements:

On both the resources, GET, POST, PUT, and DELETE operations are defined. This allows you to view, create, update, and delete workspaces and namespaces.

You have to use GET when you just want to retrieve information. If you want to create a new object, POST comes in handy. PUT is used to change properties of an existing item, while DELETE lets you remove items.

As GeoServer REST interface uses the HTTP protocol, you should always look for the return code. This lets you know whether your request was successfully implemented by the server or some errors arose.

If you changed your mind about the URI assigned to a namespace, you don't need to delete it. You can change it with a PUT request like this:

$ curl -u admin:geoserver -XPUT -H 'Content-type: text/xml' -H 'Accept: text/xml' -d '<namespace><prefix>MyOrganization</prefix><uri>http://about.me/geoserver</uri></namespace>' http://localhost:8080/geoserver/rest/namespaces/MyOrganization

Note that this time we didn't create a static file to submit information. In fact, the -d cURL parameter accepts the data on the command line as well. While this may be useful for less data, when your XML code grows, a file is a more appropriate approach.

Going to the web interface, you can see that the URI was actually changed.

The following Python code lets you perform the same operation:

>>> myUrl =  'http://localhost:8080/geoserver/rest/namespaces/MyOrganization'
>>> payload = '<namespace><prefix>MyOrganization</prefix><uri>http://about.me/geoserver</uri></namespace>'
>>> headers = {'Content-type': 'text/xml'}
>>> resp = requests.put(myUrl, auth=('admin','geoserver'), data=payload, headers=headers)
>>> resp.status_code
200

To finish our tour of workspaces operations, we have to try the DELETE option. Let's remove the MyOrganization workspace:

$ curl -u admin:geoserver -XDELETE -H 'Accept: text/xml' http://localhost:8080/geoserver/rest/workspaces/MyOrganization

Here is the command to do so in Python:

>>> myUrl =  'http://localhost:8080/geoserver/rest/workspaces/MyOrganization'
>>> headers = {'Accept': 'text/xml'}
>>> resp = requests.delete(myUrl, auth=('admin','geoserver'), headers=headers)
>>> resp.status_code
404

Can you guess why we got a 404 error?

404 stands for Not Found error (http://en.wikipedia.org/wiki/HTTP_404). You probably wondering whether the Python code contains an error.

This is not the case; it is just that we removed the workspace using cURL and obviously, you can't remove a nonexisting workspace. So, GeoServer complains when we try to remove it.