Merge lp:~wgrant/launchpad/export-archive-dependencies into lp:launchpad

[William Grant]

[William Grant (wgrant)]

= Summary =

Bug #385129 requests that archive dependencies be exported on the webservice.
This branch gives read-only access to ArchiveDependency records through the
API.

== Implementation details ==

I've given IArchiveDependency a URL and navigation
(<dependent>/+dependency/<dependency ID>). To get hold of the dependencies,
I also moved IArchive.{dependencies,getArchiveDependency} from IArchivePublic
to IArchiveView and exported them. This required some interface patches in
c.l.i._schema_circular_imports.

IComponent isn't exposed, so IArchiveDependency.component could not be
exposed directly. I followed the example of similar interfaces, instead
creating and exporting IArchiveDependency.component_name.

The other changes to IArchiveDependency are just decoration, with Choices
and Objects replaced with ReferenceChoices and References to coerce
lazr.restful into working.

== Tests ==

$ bin/test -vv -t xx-archive.txt
Running tests at level 1
Running canonical.testing.layers.PageTestLayer tests:
  Set up canonical.testing.layers.BaseLayer in 0.024 seconds.
  Set up canonical.testing.layers.DatabaseLayer in 0.521 seconds.
  Set up canonical.testing.layers.LibrarianLayer in 8.932 seconds.
  Set up canonical.testing.layers.LaunchpadLayer in 0.000 seconds.
  Set up canonical.testing.layers.FunctionalLayer in 4.414 seconds.
  Set up canonical.testing.layers.GoogleServiceLayer in 1.358 seconds.
  Set up canonical.testing.layers.LaunchpadFunctionalLayer in 0.000 seconds.
  Set up canonical.testing.layers.PageTestLayer in 0.000 seconds.
  Running:
 lib/lp/soyuz/tests/../stories/webservice/xx-archive.txt
  Ran 77 tests with 0 failures and 0 errors in 10.408 seconds.
Tearing down left over layers:
  Tear down canonical.testing.layers.PageTestLayer in 0.000 seconds.
  Tear down canonical.testing.layers.LaunchpadFunctionalLayer in 0.000 seconds.
  Tear down canonical.testing.layers.LaunchpadLayer in 0.000 seconds.
  Tear down canonical.testing.layers.LibrarianLayer in 0.312 seconds.
  Tear down canonical.testing.layers.GoogleServiceLayer in 0.051 seconds.
  Tear down canonical.testing.layers.FunctionalLayer ... not supported
  Tear down canonical.testing.layers.DatabaseLayer in 0.020 seconds.
  Tear down canonical.testing.layers.BaseLayer in 0.000 seconds.

== lint ==

Checking for conflicts. and issues in doctests and templates.
Running jslint, xmllint, pyflakes, and pylint.
Using normal rules.

Linting changed files:
  lib/canonical/launchpad/interfaces/_schema_circular_imports.py
  lib/lp/soyuz/browser/archive.py
  lib/lp/soyuz/browser/configure.zcml
  lib/lp/soyuz/interfaces/archive.py
  lib/lp/soyuz/interfaces/archivedependency.py
  lib/lp/soyuz/model/archivedependency.py
  lib/lp/soyuz/stories/webservice/xx-archive.txt

[Celso Providelo (cprov)]

On Fri, Aug 7, 2009 at 10:05 AM, William Grant<email address hidden> wrote:
> William Grant has proposed merging lp:~wgrant/launchpad/export-archive-dependencies into lp:launchpad/devel.
>
> Requested reviews:
>    Celso Providelo (cprov)
>
> = Summary =
>
> Bug #385129 requests that archive dependencies be exported on the webservice.
> This branch gives read-only access to ArchiveDependency records through the
> API.
>
>
> == Implementation details ==
>
> I've given IArchiveDependency a URL and navigation
> (<dependent>/+dependency/<dependency ID>). To get hold of the dependencies,
> I also moved IArchive.{dependencies,getArchiveDependency} from IArchivePublic
> to IArchiveView and exported them. This required some interface patches in
> c.l.i._schema_circular_imports.
>
> IComponent isn't exposed, so IArchiveDependency.component could not be
> exposed directly. I followed the example of similar interfaces, instead
> creating and exporting IArchiveDependency.component_name.
>
> The other changes to IArchiveDependency are just decoration, with Choices
> and Objects replaced with ReferenceChoices and References to coerce
> lazr.restful into working.

Hi Willian,

Thanks for working on this, You've done a fantastic job!

Comments inline.

> === modified file 'lib/canonical/launchpad/interfaces/_schema_circular_imports.py'

Nice that you've found your way through the monkey-patches :)

> === modified file 'lib/lp/soyuz/browser/archive.py'
> --- lib/lp/soyuz/browser/archive.py 2009-08-05 11:33:16 +0000
> +++ lib/lp/soyuz/browser/archive.py 2009-08-07 14:05:54 +0000
> @@ -34,6 +34,8 @@
> from zope.schema import Choice, List
> from zope.schema.vocabulary import SimpleVocabulary, SimpleTerm
>
> +from sqlobject import SQLObjectNotFound
> +
> from canonical.cachedproperty import cachedproperty
> from canonical.launchpad import _
> from lp.soyuz.browser.build import BuildRecordsView
> @@ -285,6 +287,20 @@
> else:
> return None
>
> + @stepthrough('+dependency')
> + def traverse_dependency(self, id):
> + try:
> + id = int(id)
> + except ValueError:
> + # Not a number.
> + return None
> +
> + try:
> + archive = getUtility(IArchiveSet).get(id)
> + except SQLObjectNotFound:
> + return None
> +
> + return self.context.getArchiveDependency(archive)

Okay, there are few subtle details in this travesal that I'd like to
clarify with you.

1. The protection against leaking dependencies of P3As exists because
IArchive.getArchiveDependencies() requires launchpad.View.

2. By design we don't allow public PPAs to depend on P3As, so attempts
to reach a P3A by querying its ID as a dependency of a public PPA will
never be an option (not that it would expose much of the dependant P3A
either, but ...)

Can you summarize those aspects in the traversal docstring ?

It is still possible, though, that a P3A B added as dependency of
another P3A A isn't accessible to all people with launchpad.View on A.
This situation would break most of the code in this area, including
the page rendering ... We should file a bug about it.

> class ArchiveContextMenu(Cont...

[Celso Providelo (cprov)]

review: Needs Information (code)

[Francis J. Lacoste (flacoste)]

On August 7, 2009, Celso Providelo wrote:
> Any archive purpose can contain dependencies, not only PPAs. The
> restriction can remain in the form interface
> (IArchiveEditDependenciesForm), so you don't need to modify any test.
>
> I believe you can test this by creating a dependency for a COPY
> (rebuild) archive. In the best case, I think ReferenceChoice() is
> doing nothing and could be replaced with a simple Reference() mainly
> for simplicity.

Well, if you want to check the value against a vocabulary, you need
REferenceChoice, if a simple interface check is sufficent, Reference is the
thing to use.

--
Francis J. Lacoste
<email address hidden>

[Francis J. Lacoste (flacoste)]

On August 7, 2009, Celso Providelo wrote:
> > class IArchiveDependency(Interface):
> > """ArchiveDependency interface."""
> > + export_as_webservice_entry()
> >
> > id = Int(title=_("The archive ID."), readonly=True)
> >
> > - date_created = Datetime(
> > - title=_("Instant when the dependency was created."),
> > - required=False, readonly=True)
> > -
> > - archive = Choice(
> > - title=_('Target archive'),
> > - required=True,
> > - vocabulary='PPA',
> > - description=_("The PPA affected by this dependecy."))
> > -
> > - dependency = Object(
> > - schema=IArchive,
> > - title=_("The archive set as a dependency."),
> > - required=False)
> > -
> > - pocket = Choice(
> > - title=_("Pocket"), required=True,
> > vocabulary=PackagePublishingPocket) + date_created = exported(
> > + Datetime(
> > + title=_("Instant when the dependency was created."),
> > + required=False, readonly=True))
> > +
> > + archive = exported(
> > + ReferenceChoice(
> > + title=_('Target archive'),
> > + required=True,
> > + vocabulary='PPA',
> > + schema=IArchive,
> > + description=_("The PPA affected by this dependecy.")))
> > +
>
> This was a previous design slip, not your fault, but you can probably fix
> it.
>
> Any archive purpose can contain dependencies, not only PPAs. The
> restriction can remain in the form interface
> (IArchiveEditDependenciesForm), so you don't need to modify any test.
>
> I believe you can test this by creating a dependency for a COPY
> (rebuild) archive. In the best case, I think ReferenceChoice() is
> doing nothing and could be replaced with a simple Reference() mainly
> for simplicity.
>
> > + dependency = exported(
> > + Reference(
> > + schema=IArchive,
> > + title=_("The archive set as a dependency."),
> > + required=False))
> > +
> > + pocket = exported(
> > + Choice(
> > + title=_("Pocket"), required=True,
> > + vocabulary=PackagePublishingPocket))
> >
> > component = Choice(
> > title=_("Component"), required=True, vocabulary='Component')

Another thing to watch out for here is that most of these attributes are
read/write. Is that really intented?

Shouldn't a IArchiveDependency object be a relatively immutable objects that
are created/destroyed, but not modified?

Does it make sense to change the dependency and archive attribute directly? If
not, you need to put readonly=True on those attributes.

--
Francis J. Lacoste
<email address hidden>

[William Grant (wgrant)]

On Fri, 2009-08-07 at 21:54 +0000, Celso Providelo wrote:
> [snip]
>
> Hi Willian,
>
> Thanks for working on this, You've done a fantastic job!
>
> Comments inline.

Thanks.

> > === modified file 'lib/canonical/launchpad/interfaces/_schema_circular_imports.py'
>
> Nice that you've found your way through the monkey-patches :)

Myes. A little messy.

> > === modified file 'lib/lp/soyuz/browser/archive.py'
> > [snip]
> > + @stepthrough('+dependency')
> > + def traverse_dependency(self, id):
> > + try:
> > + id = int(id)
> > + except ValueError:
> > + # Not a number.
> > + return None
> > +
> > + try:
> > + archive = getUtility(IArchiveSet).get(id)
> > + except SQLObjectNotFound:
> > + return None
> > +
> > + return self.context.getArchiveDependency(archive)
>
> Okay, there are few subtle details in this travesal that I'd like to
> clarify with you.
>
> 1. The protection against leaking dependencies of P3As exists because
> IArchive.getArchiveDependencies() requires launchpad.View.
>
> 2. By design we don't allow public PPAs to depend on P3As, so attempts
> to reach a P3A by querying its ID as a dependency of a public PPA will
> never be an option (not that it would expose much of the dependant P3A
> either, but ...)
>
> Can you summarize those aspects in the traversal docstring ?
>
> It is still possible, though, that a P3A B added as dependency of
> another P3A A isn't accessible to all people with launchpad.View on A.
> This situation would break most of the code in this area, including
> the page rendering ... We should file a bug about it.

I've addressed point 1, but omitted point 2 as discussed on IRC.

> [snip]
> > === modified file 'lib/lp/soyuz/interfaces/archivedependency.py'
> > [snip]
> > + archive = exported(
> > + ReferenceChoice(
> > + title=_('Target archive'),
> > + required=True,
> > + vocabulary='PPA',
> > + schema=IArchive,
> > + description=_("The PPA affected by this dependecy.")))
> > +
>
> This was a previous design slip, not your fault, but you can probably fix it.
>
> Any archive purpose can contain dependencies, not only PPAs. The
> restriction can remain in the form interface
> (IArchiveEditDependenciesForm), so you don't need to modify any test.
>
> I believe you can test this by creating a dependency for a COPY
> (rebuild) archive. In the best case, I think ReferenceChoice() is
> doing nothing and could be replaced with a simple Reference() mainly
> for simplicity.

I wondered about that, but decided to trust the old interface. I've
replaced it with just a Reference now.

> [snip]
> > === modified file 'lib/lp/soyuz/model/archivedependency.py'
> > --- lib/lp/soyuz/model/archivedependency.py 2009-06-25 04:06:00 +0000
> > +++ lib/lp/soyuz/model/archivedependency.py 2009-08-07 14:05:54 +0000
> > @@ -48,6 +48,14 @@
> > foreignKey='Component', dbName='component')
> >
> > @property
> > + def component_name(self):
> > + """See `IArchiveDependency`"""
> > + if self.component:
> > + return self.component.name
> ...

[Celso Providelo (cprov)]

Willian,

Thanks for addressing my comments. Not only a nice new feature but also existing code got improved.

r=me

review: Approve (code)

=== modified file 'lib/canonical/launchpad/interfaces/_schema_circular_imports.py'
--- lib/canonical/launchpad/interfaces/_schema_circular_imports.py	2009-07-17 00:26:05 +0000
+++ lib/canonical/launchpad/interfaces/_schema_circular_imports.py	2009-08-04 12:20:53 +0000
@@ -52,6 +52,8 @@
     IArchivePermission)
 from lp.soyuz.interfaces.archivesubscriber import (
     IArchiveSubscriber)
+from lp.soyuz.interfaces.archivedependency import (
+    IArchiveDependency)
 from lp.soyuz.interfaces.distroarchseries import IDistroArchSeries
 from lp.soyuz.interfaces.publishing import (
     IBinaryPackagePublishingHistory, ISecureBinaryPackagePublishingHistory,
@@ -161,6 +163,7 @@
 
 # IArchive apocalypse.
 patch_reference_property(IArchive, 'distribution', IDistribution)
+patch_collection_property(IArchive, 'dependencies', IArchiveDependency)
 patch_collection_return_type(
     IArchive, 'getPermissionsForPerson', IArchivePermission)
 patch_collection_return_type(
@@ -187,6 +190,9 @@
 patch_plain_parameter_type(IArchive, 'syncSource', 'from_archive', IArchive)
 patch_entry_return_type(IArchive, 'newSubscription', IArchiveSubscriber)
 patch_plain_parameter_type(
+    IArchive, 'getArchiveDependency', 'dependency', IArchive)
+patch_entry_return_type(IArchive, 'getArchiveDependency', IArchiveDependency)
+patch_plain_parameter_type(
     IArchive, 'getPublishedSources', 'distroseries', IDistroSeries)
 patch_collection_return_type(
     IArchive, 'getPublishedSources', ISourcePackagePublishingHistory)
 
=== modified file 'lib/lp/soyuz/browser/archive.py'
--- lib/lp/soyuz/browser/archive.py	2009-07-30 01:24:18 +0000
+++ lib/lp/soyuz/browser/archive.py	2009-08-04 03:55:04 +0000
@@ -34,6 +34,8 @@
 from zope.schema import Choice, List
 from zope.schema.vocabulary import SimpleVocabulary, SimpleTerm
 
+from sqlobject import SQLObjectNotFound
+
 from canonical.cachedproperty import cachedproperty
 from canonical.launchpad import _
 from lp.soyuz.browser.build import BuildRecordsView
@@ -285,6 +287,20 @@
         else:
             return None
 
+    @stepthrough('+dependency')
+    def traverse_dependency(self, id):
+        try:
+            id = int(id)
+        except ValueError:
+            # Not a number.
+            return None
+
+        try:
+            archive = getUtility(IArchiveSet).get(id)
+        except SQLObjectNotFound:
+            return None
+
+        return self.context.getArchiveDependency(archive)
 
 class ArchiveContextMenu(ContextMenu):
     """Overview Menu for IArchive."""
 
=== modified file 'lib/lp/soyuz/browser/configure.zcml'
--- lib/lp/soyuz/browser/configure.zcml	2009-07-18 00:05:49 +0000
+++ lib/lp/soyuz/browser/configure.zcml	2009-08-04 03:55:04 +0000
@@ -834,4 +834,9 @@
         path_expression="string:+upload/${id}"
         attribute_to_parent="distroseries"
         />
+    <browser:url
+        for="lp.soyuz.interfaces.archivedependency.IArchiveDependency"
+        path_expression="string:+dependency/${dependency/id}"
+        attribute_to_parent="archive"
+        />
 </configure>
 
=== modified file 'lib/lp/soyuz/interfaces/archive.py'
--- lib/lp/soyuz/interfaces/archive.py	2009-07-30 00:20:01 +0000
+++ lib/lp/soyuz/interfaces/archive.py	2009-08-07 12:44:22 +0000
@@ -55,8 +55,9 @@
     REQUEST_USER, call_with, export_as_webservice_entry, exported,
     export_read_operation, export_factory_operation, export_operation_as,
     export_write_operation, operation_parameters,
-    operation_returns_collection_of, rename_parameters_as, webservice_error)
-from lazr.restful.fields import Reference
+    operation_returns_collection_of, operation_returns_entry,
+    rename_parameters_as, webservice_error)
+from lazr.restful.fields import CollectionField, Reference
 
 
 class ArchiveDependencyError(Exception):
@@ -184,10 +185,6 @@
     signing_key = Object(
         title=_('Repository sigining key.'), required=False, schema=IGPGKey)
 
-    dependencies = Attribute(
-        "Archive dependencies recorded for this archive and ordered by owner "
-        "displayname.")
-
     expanded_archive_dependencies = Attribute(
         "The expanded list of archive dependencies. It includes the implicit "
         "PRIMARY archive dependency for PPAs.")
@@ -310,15 +307,6 @@
         not found.
         """
 
-    def getArchiveDependency(dependency):
-        """Return the `IArchiveDependency` object for the given dependency.
-
-        :param dependency: is an `IArchive` object.
-
-        :return: `IArchiveDependency` or None if a corresponding object
-            could not be found.
-        """
-
     def removeArchiveDependency(dependency):
         """Remove the `IArchiveDependency` record for the given dependency.
 
@@ -761,6 +749,12 @@
         description=_("The password used by the builder to access the "
                       "archive."))
 
+    dependencies = exported(
+        CollectionField(
+            title=_("Archive dependencies recorded for this archive."),
+            value_type=Reference(schema=Interface), #Really IArchiveDependency
+            readonly=True))
+
     description = exported(
         Text(
             title=_("Archive contents description"), required=False,
@@ -920,6 +914,19 @@
             given ids that belong in the archive.
         """
 
+    @operation_parameters(
+        dependency=Reference(schema=Interface)) #Really IArchive. See below.
+    @operation_returns_entry(schema=Interface) #Really IArchiveDependency.
+    @export_read_operation()
+    def getArchiveDependency(dependency):
+        """Return the `IArchiveDependency` object for the given dependency.
+
+        :param dependency: is an `IArchive` object.
+
+        :return: `IArchiveDependency` or None if a corresponding object
+            could not be found.
+        """
+
 
 class IArchiveAppend(Interface):
     """Archive interface for operations restricted by append privilege."""
 
=== modified file 'lib/lp/soyuz/interfaces/archivedependency.py'
--- lib/lp/soyuz/interfaces/archivedependency.py	2009-06-25 04:06:00 +0000
+++ lib/lp/soyuz/interfaces/archivedependency.py	2009-08-07 12:44:29 +0000
@@ -11,38 +11,54 @@
     'IArchiveDependency',
     ]
 
-from zope.interface import Attribute, Interface
-from zope.schema import Choice, Datetime, Int, Object
+from zope.interface import Interface
+from zope.schema import Choice, Datetime, Int, TextLine
 
 from canonical.launchpad import _
 from lp.soyuz.interfaces.archive import IArchive
 from lp.soyuz.interfaces.publishing import PackagePublishingPocket
+from lazr.restful.fields import Reference, ReferenceChoice
+from lazr.restful.declarations import (
+    export_as_webservice_entry, exported)
 
 
 class IArchiveDependency(Interface):
     """ArchiveDependency interface."""
+    export_as_webservice_entry()
 
     id = Int(title=_("The archive ID."), readonly=True)
 
-    date_created = Datetime(
-        title=_("Instant when the dependency was created."),
-        required=False, readonly=True)
-
-    archive = Choice(
-        title=_('Target archive'),
-        required=True,
-        vocabulary='PPA',
-        description=_("The PPA affected by this dependecy."))
-
-    dependency = Object(
-        schema=IArchive,
-        title=_("The archive set as a dependency."),
-        required=False)
-
-    pocket = Choice(
-        title=_("Pocket"), required=True, vocabulary=PackagePublishingPocket)
+    date_created = exported(
+        Datetime(
+            title=_("Instant when the dependency was created."),
+            required=False, readonly=True))
+
+    archive = exported(
+        ReferenceChoice(
+            title=_('Target archive'),
+            required=True,
+            vocabulary='PPA',
+            schema=IArchive,
+            description=_("The PPA affected by this dependecy.")))
+
+    dependency = exported(
+        Reference(
+            schema=IArchive,
+            title=_("The archive set as a dependency."),
+            required=False))
+
+    pocket = exported(
+        Choice(
+            title=_("Pocket"), required=True,
+            vocabulary=PackagePublishingPocket))
 
     component = Choice(
         title=_("Component"), required=True, vocabulary='Component')
 
-    title = Attribute("Archive dependency title.")
+    # We don't want to export IComponent, so the name is exported specially.
+    component_name = exported(
+        TextLine(
+            title=_("Component name"),
+            required=True))
+
+    title = exported(TextLine(title=_("Archive dependency title.")))
 
=== modified file 'lib/lp/soyuz/model/archivedependency.py'
--- lib/lp/soyuz/model/archivedependency.py	2009-06-25 04:06:00 +0000
+++ lib/lp/soyuz/model/archivedependency.py	2009-08-04 03:32:34 +0000
@@ -48,6 +48,14 @@
         foreignKey='Component', dbName='component')
 
     @property
+    def component_name(self):
+        """See `IArchiveDependency`"""
+        if self.component:
+            return self.component.name
+        else:
+            return None
+
+    @property
     def title(self):
         """See `IArchiveDependency`."""
         if self.dependency.is_ppa:
 
=== modified file 'lib/lp/soyuz/stories/webservice/xx-archive.txt'
--- lib/lp/soyuz/stories/webservice/xx-archive.txt	2009-07-18 11:51:59 +0000
+++ lib/lp/soyuz/stories/webservice/xx-archive.txt	2009-08-07 11:16:45 +0000
@@ -15,6 +15,7 @@
 
     >>> from lazr.restful.testing.webservice import pprint_entry
     >>> pprint_entry(cprov_archive)
+    dependencies_collection_link: u'http://.../~cprov/+archive/ppa/dependencies'
     description: u'packages to help my friends.'
     displayname: u'PPA for Celso Providelo'
     distribution_link: u'http://.../ubuntu'
@@ -77,6 +78,7 @@
     >>> main_archive = webservice.get(
     ...     ubuntutest['main_archive_link']).jsonBody()
     >>> pprint_entry(main_archive)
+    dependencies_collection_link: u'http://.../ubuntutest/+archive/primary/dependencies'
     description: None
     displayname: u'Primary Archive for Ubuntu Test'
     distribution_link: u'http://.../ubuntutest'
@@ -704,6 +706,7 @@
 the IArchive context, in this case only Celso has it.
 
     >>> pprint_entry(user_webservice.get("/~cprov/+archive/ppa").jsonBody())
+    dependencies_collection_link: u'http://.../~cprov/+archive/ppa/dependencies'
     description: u'tag:launchpad.net:2008:redacted'
     displayname: u'PPA for Celso Providelo'
     distribution_link: u'http://.../ubuntu'
@@ -715,6 +718,7 @@
     signing_key_fingerprint: u'tag:launchpad.net:2008:redacted'
 
     >>> pprint_entry(cprov_webservice.get("/~cprov/+archive/ppa").jsonBody())
+    dependencies_collection_link: u'http://.../~cprov/+archive/ppa/dependencies'
     description: u'packages to help my friends.'
     displayname: u'PPA for Celso Providelo'
     distribution_link: u'http://.../ubuntu'
@@ -878,3 +882,154 @@
     ...
     CannotCopy: private 1.1 in hoary
     (same version already uploaded and waiting in ACCEPTED queue)
+
+
+= Archive dependencies =
+
+Archives can specify dependencies on pockets and components of other
+archives. Found at <dependentarchive.id>/+dependency/<dependencyarchive.id>,
+these IArchiveDependency records can be retrieved through the API.
+
+First we'll add an explicit dependency on the primary archive to
+cprov's PPA. We can't do this through the webservice yet.
+
+    >>> from lp.soyuz.interfaces.component import IComponentSet
+    >>> from lp.soyuz.interfaces.publishing import PackagePublishingPocket
+    >>> login('[e-mail]')
+    >>> cprov_ppa_db = getUtility(IPersonSet).getByName('cprov').archive
+    >>> dep = cprov_ppa_db.addArchiveDependency(
+    ...     cprov_ppa_db.distribution.main_archive,
+    ...     PackagePublishingPocket.RELEASE,
+    ...     component=getUtility(IComponentSet)['universe'])
+    >>> logout()
+
+We can then request that dependency, and see that we get all of its
+attributes.
+
+    >>> cprov_main_dependency = webservice.named_get(
+    ...     '/~cprov/+archive/ppa', 'getArchiveDependency',
+    ...     dependency=ubuntu['main_archive_link']).jsonBody()
+    >>> pprint_entry(cprov_main_dependency)
+    archive_link: u'http://.../~cprov/+archive/ppa'
+    component_name: u'universe'
+    date_created: ...
+    dependency_link: u'http://.../ubuntu/+archive/primary'
+    pocket: u'Release'
+    resource_type_link: u'http://.../#archive_dependency'
+    self_link: u'http://.../~cprov/+archive/ppa/+dependency/1'
+    title: u'Primary Archive for Ubuntu Linux - RELEASE (main, universe)'
+
+Asking for an archive on which there is no dependency returns None.
+
+    >>> debian = webservice.get('/debian').jsonBody()
+    >>> webservice.named_get(
+    ...     '/~cprov/+archive/ppa', 'getArchiveDependency',
+    ...     dependency=debian['main_archive_link']).jsonBody()
+
+Archives will also give us a list of their custom dependencies.
+
+    >>> print_self_link_of_entries(
+    ...     webservice.get('/~cprov/+archive/ppa/dependencies').jsonBody())
+    http://.../~cprov/+archive/ppa/+dependency/1
+
+Crafting a URL to a non-dependency 404s:
+
+    >>> print webservice.get(
+    ...     '/~cprov/+archive/ppa/+dependency/2')
+    HTTP/1.1 404 Not Found
+    ...
+
+A 404 also occurs if we ask for an archive that doesn't exist.
+
+    >>> print webservice.get(
+    ...     '/~cprov/+archive/ppa/+dependency/123456')
+    HTTP/1.1 404 Not Found
+    ...
+
+== Security ==
+
+Any user can retrieve a public PPA's dependencies.
+
+    >>> login('[e-mail]')
+    >>> cprov_ppa_db.private = False
+    >>> logout()
+
+    >>> print user_webservice.get(
+    ...     '/~cprov/+archive/ppa/dependencies')
+    HTTP/1.1 200 Ok
+    ...
+
+    >>> print user_webservice.get(
+    ...     '/~cprov/+archive/ppa/+dependency/1')
+    HTTP/1.1 200 Ok
+    ...
+
+The dependencies of a private archive are private. Let's make
+Celso's PPA private.
+
+    >>> login('[e-mail]')
+    >>> cprov_ppa_db.private = True
+    >>> logout()
+
+Now our unprivileged user can't get a list of the dependencies.
+
+    >>> print user_webservice.get(
+    ...     '/~cprov/+archive/ppa/dependencies')
+    HTTP/1.1 401 Unauthorized
+    ...
+    Unauthorized: (<Archive at ...>, 'dependencies', 'launchpad.View')
+    <BLANKLINE>
+
+Nor can said user craft a URL to a dependency.
+
+    >>> print user_webservice.get(
+    ...     '/~cprov/+archive/ppa/+dependency/1')
+    HTTP/1.1 401 Unauthorized
+    ...
+    Unauthorized: (<Archive at ...>, 'getArchiveDependency', 'launchpad.View')
+    <BLANKLINE>
+
+Celso can still see them if we grant private permissions, of course.
+
+    >>> cprov_webservice = webservice_for_person(
+    ...     cprov, permission=OAuthPermission.WRITE_PRIVATE)
+    >>> print cprov_webservice.get(
+    ...     '/~cprov/+archive/ppa/dependencies')
+    HTTP/1.1 200 Ok
+    ...
+    >>> print cprov_webservice.get(
+    ...     '/~cprov/+archive/ppa/+dependency/1')
+    HTTP/1.1 200 Ok
+    ...
+
+    >>> login('[e-mail]')
+    >>> cprov_ppa_db.private = False
+    >>> logout()
+
+But even he can't write to a dependency.
+
+    >>> sabdfl_ppa = cprov_webservice.get(
+    ...     '/~sabdfl/+archive/ppa').jsonBody()
+    >>> print cprov_webservice.patch(
+    ...     '/~cprov/+archive/ppa/+dependency/1', 'application/json',
+    ...     simplejson.dumps({'archive_link': sabdfl_ppa['self_link']}))
+    HTTP/1.1 ...
+    ...
+    ForbiddenAttribute: ('archive', <ArchiveDependency at ...>)
+    <BLANKLINE>
+
+    >>> print cprov_webservice.patch(
+    ...     '/~cprov/+archive/ppa/+dependency/1', 'application/json',
+    ...     simplejson.dumps({'dependency_link': sabdfl_ppa['self_link']}))
+    HTTP/1.1 ...
+    ...
+    ForbiddenAttribute: ('dependency', <ArchiveDependency at ...>)
+    <BLANKLINE>
+
+    >>> print cprov_webservice.patch(
+    ...     '/~cprov/+archive/ppa/+dependency/1', 'application/json',
+    ...     simplejson.dumps({'pocket': 'Security'}))
+    HTTP/1.1 ...
+    ...
+    ForbiddenAttribute: ('pocket', <ArchiveDependency at ...>)
+    <BLANKLINE>