10 Apr 2009
Curl up with a good web script
Curl is a useful tool for all sorts of things. One specific example of when it comes in handy is when you are developing Alfresco web scripts. On a Surf project, for example, you might divide into a “Surf tier” team and a “Repository tier” team. Once you’ve agreed on the interface, including both the URLs and the format of the data that goes back-and-forth between the tiers, the two teams can start cranking out code in parallel.
If you’re on the repo team, you need a way to test your API, and you probably don’t have a UI to test it with (that’s what the other team’s working on). There are lots of solutions to this but curl is really handy and it runs everywhere (on Windows, use Cygwin).
This post isn’t intended to be a full reference or how-to for curl, and obviously, you can use curl for a lot of tasks that involve HTTP, not just Alfresco web scripts. Here are some quick examples of using curl with Alfresco web scripts to get you going.
Get a ticket
It’s highly likely that your web script will require authentication. So the first thing you do is call the login web script to get a ticket.
curl -v "http://localhost:8080/alfresco/service/api/login?u=admin&pw=somepassword"
Alfresco will respond with something like:
<?xml version="1.0" encoding="UTF-8"?>
Now you can take that ticket and append it to your subsequent web script calls.
Any web script you’ve got that accepts GET can be tested using the same simple syntax.
Post JSON to your custom web script
If all you had were GETs you’d probably just test them in your browser. POSTs, PUTs and DELETEs require a little more doing to test. You’re going to want to test those web scripts so that when the front-end team has their stuff ready, it all comes together without a lot of fuss.
So let’s say you’ve got a web script that the front-end will be POSTing JSON to. To test it out, create a file with some test JSON, then post it to the web script using curl, like this:
curl -v -X POST "http://localhost:8080/alfresco/service/someco/someScript?alf_ticket=TICKET_e46107058fdd2760441b44481a22e7498e7dbf66" -H "Content-Type: application/json" -d @/Users/jpotts/test.json
var postedObject = eval('(' + json + ')');
logger.log("Customer name:" + postedObject.customerName);
Run a CMIS query
With 3.0 Alfresco added an implementation of the proposed CMIS spec to the product. CMIS gives you a Web Services API, a RESTful API, and a SQL-like query language. Once you figure out the syntax, it’s easy to post CMIS queries to the repository. You can wrap the CMIS query in XML:
<cmis:query xmlns:cmis="http://www.cmis.org/2008/05" >
<cmis:statement><![CDATA[select * from cm_content where cm_name like '%Foo%']]></cmis:statement>
Then post it using the same syntax as you saw previously, but with a different Content-Type in the header, like this:
curl -v -X POST "http://localhost:8080/alfresco/service/api/query?alf_ticket=TICKET_e46107058fdd2760441b44481a22e7498e7dbf66" -H "Content-Type: application/cmisquery+xml" -d @/Users/jpotts/cmis-query.xml
Alfresco will respond with ATOM, but it’s a little verbose so I won’t take up space here to show you the result. Also, I noticed this bombed when I ran it against 3.1 Enterprise but I haven’t drilled down on why yet.
Create a new object using CMIS ATOM
Issuing a GET against a CMIS URL returns ATOM. But CMIS URLs can also accept POSTed ATOM to do things like create new objects. For example, to create a new content object you would first create the ATOM XML:
<?xml version="1.0" encoding="utf-8"?>
<entry xmlns="http://www.w3.org/2005/Atom" xmlns:cmis="http://www.cmis.org/2008/05">
<title>Test Plain Text Content</title>
<summary>Plain text content created via CMIS POST</summary>
Note that the content has to be Base64 encoded. In this case, the content is plain text that reads, “Here is some plain text content.” One way to encode it is to use OpenSSL like “openssl base64 -in <infile> -out <outfile>”. The exact syntax of ATOM XML with CMIS is the subject for another post.
Once you’ve got the XML ready to go, post it using the same syntax shown previously, with a different Content-Type in the header:
curl -v -X POST "http://localhost:8080/alfresco/service/api/node/workspace/SpacesStore/18fd9821-42a5-4c6a-86d3-3f252679cf7d/children?alf_ticket=TICKET_e46107058fdd2760441b44481a22e7498e7dbf66" -H "Content-Type: application/atom+xml" -d @/Users/jpotts/testCreate.atom.xml
The node reference in the URL above is a reference to the folder in which this new child will be created. There’s also a similar URL that uses the path instead of a node ref if that’s more your thing.
Refreshing Web Scripts from Ant
One of the things you do quite frequently when you develop web scripts is tell Alfresco to refresh its list of web scripts. There are lots of ways to automate this, but one is to create an Ant task that uses curl to invoke the web script refresh URL. This lets you deploy your changes and tell Alfresco to refresh the list in one step (and makes sure you and your teammates never forget to do the refresh).
<target name="deploy-webscripts" depends="deploy" description="Refreshes the list of webscripts">
In this example, the “deploy” ant task this task depends on is responsible for copying the web scripts to the appropriate place in the exploded Alfresco WAR. (Thanks to my colleague Eric Shea (http://www.eshea.net/2009/01/30/alfresco-dev-survivors-kit-part-1/) for this tip).
So there you go. It’s not Earth-shattering but it might give you a productivity boost if you don’t already have curl or an alternative already in your bag of tricks.