Flexible HttpClient configuration for interactions with Fedora #113

birkland · 2017-05-03T20:29:13Z

Allows the user to provide an HttpClient for interacting with Fedora, and provides for more flexible authn configuration of the default/provided HttpClient used by API-X for this purpose. This allows API-X to adapt to arbitrarily complex authn protocols that may protect Fedora (such as JWT)

In OSGi, API-X uses the highest ranked HttpClient published to the service registry for communication with Fedora.
API-X listens for added/removed HttpClients in the OSGi service registry, and immediately starts using HttpClients as soon as they are available.
Additional configuration properties are provided for using basic auth with the default HttpClient used by API-X.
The Fedora instance used in the ITs has been updated to require a username/passwd via basic auth

Resolves #112
Resolves #114

This provides a new configuration parameter for org.fcrepo.apix.jena.cfg: The httpclient.osgi.jndi.service.name property can be used to specify the service name in OSGi for HttpClient implementations. This allows the use of custom-configured HttpClient instances by the various API-X registries when communicating with Fedora.

ajs6f · 2017-05-05T14:14:04Z

fcrepo-api-x-jena/src/main/java/org/fcrepo/apix/jena/impl/HttpClientFetcher.java

+     */
+    public CloseableHttpClient getClient() throws Exception {
+
+        final Collection<ServiceReference<CloseableHttpClient>> refs = bundleContext.getServiceReferences(


After a lot of debugging, I finally realized that the reason I haven't gotten my PR to work against your PR is because I am publishing an HttpClient and you are expecting a CloseableHttpClient. What is the reason you are requiring a CloseableHttpClient (which is an impl class) instead of the interface...? Presumably, you are not actually closing the client...

Ah, it's because CloseableHttpClient is the only way to get CloseableHttpResponses that can be used with try-with-resources. I think we'd have to resort to casting or factor out the try-with-resources in order to support plain ol' HttpClient. Casting in HttpClientFetcher might actually work. Thoughts?

My first thought is that this isn't our fault, this is a real flaw in the API. I hope they are fixing this for 5. Be that as it may, and given that the only actual impls of the interface that come with Commons itself are all CloseableHttpClients, I don't have a big problem with casting (accompanied by a TODO and even maybe a ticket to remind to do better when we can).

Alternatively, we can register, not the client, but the interceptor. IOW, you build your own client in API-X (presumably via one of the HttpClientBuilderFactory services that HTTP Commons registers for you) and draw any HttpRequestInterceptors or HttpResponsenterceptors registered under the right filters and pack them on.

Does either sound inherently more appealing? The latter is "cleaner", but really starts to tangle the Commons HTTP client API into our code.

Yeah, an API flaw (probably for the sake of backward compatibility with pre-java-7).

Of all those, I think casting is more appealing. I don't know enough about HttpClient to have a sense of whether interceptors would be sufficient.

OK, I'll push to the PR once it passes its local ITs

Oh, interceptors are sufficient-- that's what we are using on the CLAW-supplied client we are offering you to inject. That having been said, I have no prob with casting, since that means less work for me. :)

After a few false starts getting OSGi wiring happy, I just updated the PR to use the casting approach. Now it looks for org.apache.http.client.HttpClient!

Building it now.

Any provided HttpClient now is (a) accessible by an HttpClientFetcher, and (b) is the basis of the default registry.

Switch out current or default HttpClient for highest-ranked HttpClient in OSGi service registry immediately when it becomes available

Also place an authenticated HttpClient in fcrepo-api-x-test and publish as an OSGi service

This doesn't quite work yet, so service indexing ITs are disabled

birkland · 2017-05-11T14:35:11Z

As noted in a comment on the CLAW issue, updates to the service indexing ITs are pending

birkland · 2017-05-11T20:59:05Z

@ajs6f @acoburn

Just FYI, I was able to get the camel http4 component to use a provided HttpClient by adding the param
?httpClient=#httpClient to an http4 endpoint URI, and having a bean with id of httpClient available in blueprint. It doesn't look like this is documented anywhere I could find, except via looking through the source code. It should work for using the JWT-enabled CLAW HttpClient in camel routes.

ajs6f · 2017-05-12T00:53:53Z

Tracking the question of httpClient here.

birkland mentioned this pull request May 3, 2017

First draft of a simple auth-aware HttpClient service Islandora/Alpaca#40

Merged

ajs6f reviewed May 5, 2017

View reviewed changes

birkland added 8 commits May 5, 2017 13:00

Use HttpClient interface in OSGi registry

ea9cdb3

Use provided HttpClient in base registry

c3fc568

Any provided HttpClient now is (a) accessible by an HttpClientFetcher, and (b) is the basis of the default registry.

Fix blueprint to inject the correct HttpClient

e769c99

Use injected HttpClient instead of FcrepoClient

69cab8a

Proxy HttpClient, listen for OSGi services

3e404f7

Switch out current or default HttpClient for highest-ranked HttpClient in OSGi service registry immediately when it becomes available

Bump fcrepo, cargo versions

db3ecc2

Use basicAuth in Fedora for ITs

b65da6b

Also place an authenticated HttpClient in fcrepo-api-x-test and publish as an OSGi service

Use authenticated fcrepo camel component for index

fea5b57

This doesn't quite work yet, so service indexing ITs are disabled

birkland changed the title ~~Configure OSGi service reference name for HttpClient~~ Flexible HttpClient configuration for interactions with Fedora May 11, 2017

ajs6f mentioned this pull request May 11, 2017

504: Adding API-X to claw_vagrant islandora-deprecated/claw_vagrant#40

Merged

birkland added 2 commits May 11, 2017 16:51

Use provided HttpClient for indexing camel routes

5f10d5a

Update README.md for http configuration

4c287b8

birkland added 2 commits May 12, 2017 11:16

Be more cautious with provided HttpClient

1db3192

Clean up logging

99837d1

emetsger merged commit 9fe9028 into fcrepo4-labs:master May 15, 2017

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Flexible HttpClient configuration for interactions with Fedora #113

Flexible HttpClient configuration for interactions with Fedora #113

birkland commented May 3, 2017 •

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birkland commented May 11, 2017

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ajs6f commented May 12, 2017

Flexible HttpClient configuration for interactions with Fedora #113

Flexible HttpClient configuration for interactions with Fedora #113

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