Web Services Examples

So, now that you've been through the documentation on the API Concepts, XML Format and REST API, let's take a look at a few practical examples of working with the Directed Edge webservices.

For these examples we'll be using the command line tool curl to upload XML to the webservices.

Importing a database

Let's start with a very simple database with three users (with the IDs user1, user2 and user3) and three products (with the IDs product1, product2 and product3).

<?xml version="1.0" encoding="UTF-8"?>
<directededge version="0.1">
  <item id="user1">
    <tag>user</tag>
    <link>product1</link>
    <link>product2</link>
  </item>
  <item id="user2">
    <tag>user</tag>
    <link>product3</link>
  </item>
  <item id="user3">
    <tag>user</tag>
    <link>product2</link>
  </item>
  <item id="product1">
    <tag>product</tag>
  </item>
  <item id="product2">
    <tag>product</tag>
  </item>
  <item id="product3">
    <tag>product</tag>
  </item>
</directededge>

Curl Command (Download XML):

$ curl -T database.xml https://exampledb:password@webservices.directededge.com/api/v1/exampledb

This imports the structure above into the exampledb database.

Exporting a database

Curl Command:

$ curl https://exampledb:password@webservices.directededge.com/api/v1/exampledb

Produces:

<?xml version="1.0" standalone="yes"?>

<directededge version="0.1">
  <item id="user1">
    <tag>user</tag>
    <link>product1</link>
    <link>product2</link>
  </item>
  <item id="user2">
    <tag>user</tag>
    <link>product3</link>
  </item>
  <item id="user3">
    <tag>user</tag>
    <link>product2</link>
  </item>
  <item id="product1">
    <tag>product</tag>
  </item>
  <item id="product2">
    <tag>product</tag>
  </item>
  <item id="product3">
    <tag>product</tag>
  </item>
</directededge>

Which is what we imported just above.

Adding an item

Adds a user with the ID user4 to the database.

<?xml version="1.0" encoding="UTF-8"?>
<directededge version="0.1">
  <item id="user4">
    <tag>user</tag>
  </item>
</directededge>

Curl Command (Download XML):

$ curl -T user4.xml https://exampledb:password@webservices.directededge.com/api/v1/exampledb/user4

Updating an item

Here we update the item above, but this time add the property city. This overwrites all current contents of the item.

<?xml version="1.0" encoding="UTF-8"?>
<directededge version="0.1">
  <item id="user4">
    <tag>user</tag>
    <property name="city">Berlin</property>
  </item>
</directededge>

Curl Command (Download XML):

$ curl -T user4-update.xml https://exampledb:password@webservices.directededge.com/api/v1/exampledb/user4

Adding a tag to an item

Here we add the tag Berliner to the user that we created / updated in the previous sections. As noted in the XML Format description, here we're allowed to omit the item's ID.

<?xml version="1.0" encoding="UTF-8"?>
<directededge version="0.1">
  <item>
    <tag>Berliner</tag>
  </item>
</directededge>

Curl Command (Download XML):

$ curl -T tag.xml https://exampledb:password@webservices.directededge.com/api/v1/exampledb/user4/add

Adding a link to an item

This creates a link from our recently created user to product3. Again, since we're updating the item we can omit the item ID.

<?xml version="1.0" encoding="UTF-8"?>
<directededge version="0.1">
  <item>
    <link>product3</link>
  </item>
</directededge>

Curl Command (Download XML):

$ curl -T link.xml https://exampledb:password@webservices.directededge.com/api/v1/exampledb/user4/add

Adding a property to an item

Sets the value of the property country to Germany.

<?xml version="1.0" encoding="UTF-8"?>
<directededge version="0.1">
  <item>
    <property name="country">Germany</property>
  </item>
</directededge>

Curl Command (Download XML):

$ curl -T property.xml https://exampledb:password@webservices.directededge.com/api/v1/exampledb/user4/add

Add several tags / properties / links to an item

Just like you can add single tags, properties or links to an item, you can also add (or remove) several at a time:

<?xml version="1.0" encoding="UTF-8"?>
<directededge version="0.1">
  <item>
    <tag>German</tag>
    <property name="first name">Matthias</property>
    <property name="last name">Schmidt</property>
    <link>product2</link>
  </item>
</directededge>

Curl Command (Download XML):

$ curl -T several.xml https://exampledb:password@webservices.directededge.com/api/v1/exampledb/user4/add

Removing a tag from an item

Just like we could add a tag to an item incrementally, we can remove a tag (or property, or link) by uploading the same content to the remove sub-resource.

<?xml version="1.0" encoding="UTF-8"?>
<directededge version="0.1">
  <item>
    <tag>Berliner</tag>
  </item>
</directededge>

Curl Command (Download XML):

$ curl -T tag.xml https://exampledb:password@webservices.directededge.com/api/v1/exampledb/user4/remove

Removing a link from an item

And now we can do the same with removing the link to product3:

<?xml version="1.0" encoding="UTF-8"?>
<directededge version="0.1">
  <item>
    <link>product3</link>
  </item>
</directededge>

Curl Command (Download XML):

$ curl -T link.xml https://exampledb:password@webservices.directededge.com/api/v1/exampledb/user4/remove

Retrieving an item

Now that we've made a number of changes to the item that we've been working with, let's see what the current state of it in the database is:

Curl Command:

$ curl https://exampledb:password@webservices.directededge.com/api/v1/exampledb/user4

Produces:

<?xml version="1.0" standalone="yes"?>

<directededge version="0.1">
  <item id="user4">
    <tag>German</tag>
    <tag>user</tag>
    <link>product2</link>
    <property name="first name">Matthias</property>
    <property name="last name">Schmidt</property>
    <property name="city">Berlin</property>
    <property name="country">Germany</property>
  </item>
</directededge>

Deleting an item

And now let's clear out the item we've been working with from the database.

Curl Command:

$ curl -X DELETE https://exampledb:password@webservices.directededge.com/api/v1/exampledb/user4