[Seaside] requestContext and extra data in the output

Tue Nov 23 05:32:08 UTC 2010

2010/11/22 Brian Tabone <brian.tabone at gmail.com>:
> My question is about extra data I am seeing when using the
> requestContext to send back JSon data for a web service.
>
> I am using Seaside 3.0 in Pharo 1.1
>
> My renderContentOn:html method is:
>
> renderContentOn: html
>        | resultDictionary |
>        self requestContext
>                respond: [:response |
>                        resultDictionary := Dictionary new.
>                        createError isNil
>                                ifTrue: [resultDictionary at: #listName put: listName.
>                                        resultDictionary at: #listUUID put: todoList uuid asString]
>                                ifFalse: [resultDictionary at: #error put: createError class asString.
>                                        resultDictionary at: #reason put: createError asString].
>                        response contentType: 'application/json'.
>                        response nextPutAll: resultDictionary asJson].
>
> When I call the url for this web service, I get (here is the verbose
> output from curl)
>
> curl -v http://localhost:8081/createList
> * About to connect() to localhost port 8081 (#0)
> *   Trying 127.0.0.1... connected
> * Connected to localhost (127.0.0.1) port 8081 (#0)
>> GET /createList HTTP/1.1
>> User-Agent: curl/7.19.7 (universal-apple-darwin10.0) libcurl/7.19.7 OpenSSL/0.9.8l zlib/1.2.3
>> Host: localhost:8081
>> Accept: */*
>>
> < HTTP/1.1 200 OK
> < Date: Mon, 22 Nov 2010 21:17:48 GMT
> < Connection: close
> < Server: KomHttpServer/7.1.3 (Mac OS)
> < Content-type: application/json
> < Content-length: 465
> <
> * Closing connection #0
> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
> "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"><html
> xmlns="http://www.w3.org/1999/xhtml" xml:lang="en"
> lang="en"><head><title>Seaside</title><meta http-equiv="Content-Type"
> content="text/html;charset=utf-8"/><meta
> http-equiv="Content-Script-Type"
> content="text/javascript"/></head><body
> onload="onLoad()">{"reason":"MessageNotUnderstood: receiver of
> \"asSymbol\" is nil","error":"MessageNotUnderstood"}
>
> Long story short, How do I get rid of the <html header data that is in
> the buffer before I get a hold of the response to put my JSon data in
> the stream? Should I re-initialize the response with a fresh buffer?

Nope. You're in the render phase, you should render HTML. If you want
to return JSON you can do that in the callback phase. If you're
building a web service you shouldn't use components at all.

Cheers
Philippe