Add outputFormat as a none-custom param of MapfishPrintProvider

[bentrm]

I have the requirement to "print" other formats than pdf via Geoserver printing and thought this may be interesting for upstream as well.
Right now I have problems to configure Geoserver printing to work with other formats than PDF so this has not been tested "live" but only via programmatic tests. I also changed the print-form example to include the outputFormat option but the hosted printing service also fails on delivering the supported formats (as of info.json it should deal with PNG for example).

Error while generating PDF:
java.lang.RuntimeException: java.io.IOException: Cannot run program "/usr/bin/convert": error=2, Datei oder Verzeichnis nicht gefunden
    at org.mapfish.print.output.NativeProcessOutputFactory$ImageOutput.print(NativeProcessOutputFactory.java:202)
    at org.mapfish.print.MapPrinter.print(MapPrinter.java:184)
    at org.mapfish.print.servlet.MapPrinterServlet.doCreatePDFFile(MapPrinterServlet.java:336)
    at org.mapfish.print.servlet.MapPrinterServlet.createAndGetPDF(MapPrinterServlet.java:155)
    at org.mapfish.print.servlet.MapPrinterServlet.doGet(MapPrinterServlet.java:86)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:621)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:224)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:169)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:987)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:579)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:307)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:745)
Caused by: java.io.IOException: Cannot run program "/usr/bin/convert": error=2, Datei oder Verzeichnis nicht gefunden
    at java.lang.ProcessBuilder.start(ProcessBuilder.java:1047)
    at org.mapfish.print.output.NativeProcessOutputFactory$ImageOutput.createImage(NativeProcessOutputFactory.java:277)
    at org.mapfish.print.output.NativeProcessOutputFactory$ImageOutput.print(NativeProcessOutputFactory.java:193)
    ... 22 more
Caused by: java.io.IOException: error=2, Datei oder Verzeichnis nicht gefunden
    at java.lang.UNIXProcess.forkAndExec(Native Method)
    at java.lang.UNIXProcess.<init>(UNIXProcess.java:186)
    at java.lang.ProcessImpl.start(ProcessImpl.java:130)
    at java.lang.ProcessBuilder.start(ProcessBuilder.java:1028)
    ... 24 more

If I understand this correctly the printing plugin is trying to convert the generated PDF via ImageMagick command into the desired outputFormat as requested via POST to create.json (described here).

[weskamm]

but the hosted printing service also fails on delivering the supported formats

Has been fixed on the server side, the servlet used in the examples now supports image output, tested for jpg and png

[bentrm]

The changes seem to be fine then. Thank you. Off to configuring my service correctly next.

[marcjansen]

Is this waiting for review? @weskamm, any chance you may want to do it?

[weskamm]

I'm having a look at this just right now..

[bentrm]

Thanks @weskamm. I think it's ready for review.

[weskamm]

needs adjustments from c&p

[weskamm]

I just added a minor comment. Otherwise, this looks good to me, thanks for the contribution!

[bentrm]

Is this interesting for upstream? Otherwise I will close the PR.

[marcjansen]

@weskamm?

[weskamm]

Yes i still think it is a nice addition. And as it keeps the PDF format as the default, i dont't see any problems here merging this into upstream and will do so now!