Apk: Json output with gzip

[afischerdev]

This is a call to all app developers using BRouter as a routing engine.

As part of the changes to the output routines #646, the Json output should also be available as gzip when called with parameter acceptCompressedResult=true.

Please see line 103

brouter/brouter-routing-app/src/main/java/btools/routingapp/BRouterService.java

Lines 102 to 104 in c647305

	String gpxMessage = worker.getTrackFromParams(params);
	if (canCompress && gpxMessage.startsWith("<")) {
	try {

Otherwise, the size will cause the service interface to break sooner than for a GPX output.

[devemux86]

We could also encode the polyline of the path coordinates?
(could be as option)

https://developers.google.com/maps/documentation/utilities/polylinealgorithm

All online routers do this by significantly reducing the size of their json responses.

[afischerdev]

@devemux86
Thanks for the link.
I didn't know that before.

Minify is another idea, I was able to save more than half of the space (json) - without gzip.
And all clients should be able to read this without changing the code.

[afischerdev]

A short json size test - Hannover Frankfurt trekking ~350km:
json out size 764508
minity out size 645464
gzip out size 213615

json out size 764504
gzip out size 220431

time minify ~170ms - a regex logic was used
time gzip ~70ms - both variantes