Add POST support

[roxspring]

• UML content can be POSTed to the same base URL, without url length limits.
• PSystemError diagrams results generate 400 Bad Request status codes

Curl example usage:

curl --data-binary @sample.plantuml http://localhost:8080/png/ > sample.png

Addresses #69, #25

[arnaudroques]

Many thanks for your contribution.

Returning 400 Bad Request status codes in case of syntax error is indeed a good idea.
Are you using this return code in some way ?

However, it seems that "badRequestOnError" is unused in:
void sendDiagram(String uml, int idx, boolean badRequestOnError)

Could you remove it from your merge request ?
Thanks,

[roxspring]

Doh - was doing some last minute testing of 400 Bad Request responses for GETs and clearly left it that way when committing - sorry!

It does seem that at least Safari is happy to continue showing the PSystemError diagrams even when returned with a 400 status code, and I'd expect other browsers to do the same. I'll remove the parameter as you suggest.

Using a 400 makes it much easier for programmatic clients to use common http libraries which then notice the error without needing to understand plantuml specific headers.

[qjebbs]

Thanks for your work. Can you tell how do I get second page with POST? Like what we do in GET:

http://www.plantuml.com/plantuml/svg/0/SoWkIImgAStDuNBAJrBGjLDmpCbCJbMmKYX8J4zLCEJAIoq7iR3A6d4vfEQb0FK20000

http://www.plantuml.com/plantuml/svg/1/SoWkIImgAStDuNBAJrBGjLDmpCbCJbMmKYX8J4zLCEJAIoq7iR3A6d4vfEQb0FK20000

Does POST support compressed diagram? like:

SoWkIImgAStDuNBAJrBGjLDmpCbCJbMmKYX8J4zLCEJAIoq7iR3A6d4vfEQb0FK20000

[qjebbs]

I see, I have to construct a valid GET URL, like http://www.plantuml.com/plantuml/svg/1/om80, and POST to it to get the right page.

I think it's kind of a bug, when I tries post to http://www.plantuml.com/plantuml/svg/1, I can never get the expected result.

[roxspring]

I've never used multiple pages so certainly didn't test it when implementing this feature. Looking at the code though, it appears that so long as a slash is present after the number then the index should be honoured. e.g.

• POST /plantuml/svg/7/asdbfsadfasdfasdf should show page 7 and ignore trailing asdbfsadfasdfasdf
• POST /plantuml/svg/7/ should show page 7
• POST /plantuml/svg/7 should default to page 0, treating 7 as trailing nonsense
• POST /plantuml/svg/ defaults to page 0

This all comes about due to reusing the same URL parsing pattern as used when processing GET requests - there's room for improvement :)

POST does not support compressed diagrams - I assumed compression would be better handled using a filter or proxy implementing HTTP Transfer-Encoding.

[qjebbs]

@roxspring According to my test, this is the only way to get right result:

• POST /plantuml/svg/7/\w{4,}, like POST /plantuml/svg/1/aaaa

I tested with /plantuml/svg/7/a but failed, so I thought I need to construct the url.

Following are all failed:

• POST /plantuml/svg/1/a
• POST /plantuml/svg/1/aaa
• POST /plantuml/svg/1/

You can quickly reproduce with:

@startuml
!define send(sneder,reciever,message) sneder->reciever : message
send(Alice, Bob, Hello)
newpage
send(Bob,Alice,OK)
@enduml

and:

curl --data-binary @test.wsd http://some.server/png/1/aa > sample.png
curl --data-binary @test.wsd http://some.server/png/1/> sample.png
curl --data-binary @test.wsd http://some.server/png/1/aaaa > sample.png

Only the last command works as expected, get the 'OK' message within the 2nd page.

[qjebbs]

@roxspring Can you take a look at this issue: #125. Many thanks!