Convert Hypercube and Houdini to respect Apix-Ldp-Resource header

[dannylamb]

Relevant reading: https://github.com/fcrepo4-labs/fcrepo-api-x/blob/master/src/site/markdown/execution-and-routing.md#endpoint-example

When Api-X will foward a request to a microservice, it will enrich the message with an Apix-Ldp-Resource header. Instead of reading in the path from the url and combining that with the Fedora base url, we should simply use this header provided by Api-X in Hypercube and Houdini. This means the endpoints will not have any route parameters, and we'll need to use a before middleware to manually execute the FedoraResourceConverter and jam it into the request.

It's a bit tough to set things on the Request, so it may be easier to duplicate it and provide the response from Chullo in the attribute parameter.

Controllers will also need to be touched up to retrieve the response from Chullo, as it will no longer be provided as a route parameter.

[whikloj]

Soooo this might be a good place for a couple questions and to reveal my lack of grasp of API-X.

To start, would Houdini and Hypercube be Resource scope services?

[whikloj]

@dannylamb So after reading the "Generic Endpoint Proxy" example you linked to I have a couple questions.

1. Not exactly clear how we expose these API-X services, so would Houdini become

   Apix-Exposed-Uri: http://islandora.ca/services/objectFoo/svc:Houdini/convert/

2. Using Houdini as the example, is the plan to continue to use the X-Islandora-Args header to determine resizing, etc? So in which case the request would come as

GET /houdini/convert
Host: islandora.ca
Accept: image/jpeg
User-Agent: whatever
X-Islandora-Args: -resize 10%
Apix-Ldp-Resource: http://fedora01.backend.local/repository/objectFoo/
Apix-Exposed-Uri: http://islandora.ca/services/objectFoo/svc:Houdini/convert/

[whikloj]

It appears that instead we should be specify presets, so a request to /services/houdini would return a menu of possible choices (following in the API-X examples).

GET /services/houdini
Host: islandora.ca
Accept: */*
User-Agent: whatever
Apix-Ldp-Resource: http://fedora01.backend.local/repository/objectFoo/
Apix-Exposed-Uri: http://islandora.ca/services/objectFoo/svc:Houdini

which replies (I was going to do JSON-LD, but that is sooo painful to write by hand)

HTTP/1.1 200 OK
Content-Type: text/turtle; charset=UTF-8
Allow: HEAD, OPTIONS, GET
Content-Length: 123

@prefix islandApix: <http://islandora.ca/apixService>
<> a islandApix:serviceMenu ;
   islandApix:hasService <convert> ;
   islandApix:hasService <identify> .

<identify> a islandApix:subService .

<convert> a islandApix:subService ;   
   islandApix:provides ["image/jpeg", "image/tiff", "image/png", "image/gif"] ;
   islandApix:accepts  "X-Islandora-Args" .

Is that at all close to how this should work?

[dannylamb]

I think maybe instead of thinking of it as two services, i'd treat each as its own service. E.g. http://localhost:8080/fcrepo/rest/some-image/svc:identify and http://localhost:8080/fcrepo/rest/some-image/svc:convert. Does that simplify things?

[whikloj]

Sure, so the other part is do we define a set of service options or do we advertise the header somehow? Like do we say that svc:convert does a LargeImage and a MediumImage and a SmallImage or do we say define dimensions with this format in this header?

The latter seems more flexible but also harder to express in the "service menu" thingy.

[dannylamb]

@whikloj I'm gonna do the coding quickly here to have the services accept those headers, and then we'll address your other concerns under the umbrella of #612.

[dannylamb]

Testing Instructions

To deploy the changes:

• vagrant ssh
• cd /var/www/html/Crayfish
• git remote add danny https://github.com/dannylamb/Crayfish.git
• git fetch
• git checkout issue-611
• cd /var/www/html/Crayfish/Hypercube/vendor/islandora/crayfish-commons
• git remote add danny https://github.com/dannylamb/Crayfish-Commons.git
• git fetch
• git checkout issue-611
• cd /var/www/html/Crayfish/Houdini/vendor/islandora/crayfish-commons
• git remote add danny https://github.com/dannylamb/Crayfish-Commons.git
• git fetch
• git checkout issue-611

Then ingest a tiff into Fedora, I put mine at http://localhost:8080/fcrepo/rest/test.tiff.

curl -i -H "Authorization: Bearer islandora" -H "Apix-Ldp-Resource: http://localhost:8080/fcrepo/rest/test.tiff" "http://localhost:8000/hypercube/" should return 200 and the OCR of the tiff.

curl -i -H "Authorization: Bearer islandora" -H "Apix-Ldp-Resource: http://localhost:8080/fcrepo/rest/test.tiff" "http://localhost:8000/houdini/identify" should return 200 and the json describing the image.

curl -H "Authorization: Bearer islandora" -H "Apix-Ldp-Resource: http://localhost:8080/fcrepo/rest/test.tiff" -H "Accept: image/png" "http://localhost:8000/houdini/convert" > test.png should return 200 and get you a png version of the image.

[dannylamb]

@Islandora-CLAW/committers ^^

[whikloj]

Nice work @dannylamb, I'll spin these up tonight. 👍

[whikloj]

Worked as described

[whikloj]

Resolved with Islandora/Crayfish@ad6d957 and Islandora/Crayfish-Commons@f653297