JSON network request

Getting Started Newbie Questions
#1

I am doing a simple network request where I receive the results in XML format. Is there a way to receive the results in JSON format (or this is up to the server what format to respond )?

local function networkListener( event )     if ( event.isError ) then         print( "Network error!" )     else         print ( "RESPONSE: " .. event.response )     end     local saveData = event.response local path = system.pathForFile( "myfile.txt", system.DocumentsDirectory ) local file = io.open( path, "w" ) file:write( saveData ) io.close( file ) file = nil end network.request( "http://www.carsales.com.au/cars/results?area=Stock&vertical=car&sortBy=TopDeal&q=(((Make%3D%5BToyota%5D)%26(Model%3D%5BCamry%5D))%26(Service%3D%5BCarsales%5D)%26(Year%3drange%5b2015..2015%5d))&WT.z\_srchsrcx=makemodel/format=json", "GET", networkListener, params )
#2

Here u go

display.setStatusBar( display.HiddenStatusBar ) local json = require ("json") temp\_json = { time = "", milliseconds\_since\_epoch = "", date = "", } function IsInString(theString, theText) print("IsInString()") if (tonumber(string.find(theString, theText)) == nil) then print(" String Not Found."); return false; else -- check the pos if the string to confirm (not nil is not enough) if (tonumber(string.find(theString, theText)) \> 1) then print(" String Found."); return true; else print(" String Not Found."); return false; end end end local function processDownloadedData( event ) print("processDownloadedData()") local retval local dataReceived = false if ( event.isError ) then --Hostname not found? else if (event.response == nil) then -- Error - Unknown Error elseif (event.response == "") then -- Error - Unknown Error elseif (IsInString(event.response, "time") == true) then dataReceived = true --Decode temp\_json = nil; temp\_json = json.decode(event.response); elseif (IsInString(event.response, "error") == true) then --unauthorized if (IsInString(event.response, "unauthorized") == true) then retval = native.showAlert( "Error", "Unnauthorized" , { "OK" }, onGenericAlertBox) end end if temp\_json == false then -- No Data. - Thre was no data returned. else -- now do something with the data print("--json-data----------------------------------------------------------------------------") print("time: " .. tostring(temp\_json.time)); print("offset: " .. tostring(temp\_json.milliseconds\_since\_epoch)); print("date: " .. tostring(temp\_json.date)); print("---------------------------------------------------------------------------------------") end end end -- prepare the network request function getJSONData(url, action, in\_json, callback) print("getJSONData()") local json = require ( "json" ) local headers = {} -- headers["Authorization"] = "Basic " .. mime.b64( "username:password" ) headers["Content-Type"] = "application/json" local params = {} params.headers = headers params.body = json.encode( in\_json ) network.request ( url, action, callback, params ) end -- Call the Data (background Call so it wont pause your app) getJSONData("http://date.jsontest.com", "GET", temp\_json, processDownloadedData)
#3

Uncommon the Authorisation line to add username and password to the host headers.

Also add code to check the strong returned, you may get a valid son file but unexpected contents to check the contents.

#4

Thanks mate. I tried this on other websites but it doesn’t seem to be working. My main question is do all websites allow requesting data in JSON format?

Thanks

Amir

#5

All data coming from websites has to be send in the right format. You cant just add “format=json” to the sent URL and expect the server to reconfigure the data on the way out.

#6

Check some of these links out to learn more about JSON.  JSON is my preferred data exchange format over say XML.

http://www.google.com.au/search?safe=active&q=json&oq=json&gs_l=serp.3…1320.1624.0.2008.4.4.0.0.0.0.0.0…0.0.msedr…0…1c.1.64.serp…4.0.0.tXR1A-zC2Qc

#7

No worries mate. I get it now.

#8

Here u go

display.setStatusBar( display.HiddenStatusBar ) local json = require ("json") temp\_json = { time = "", milliseconds\_since\_epoch = "", date = "", } function IsInString(theString, theText) print("IsInString()") if (tonumber(string.find(theString, theText)) == nil) then print(" String Not Found."); return false; else -- check the pos if the string to confirm (not nil is not enough) if (tonumber(string.find(theString, theText)) \> 1) then print(" String Found."); return true; else print(" String Not Found."); return false; end end end local function processDownloadedData( event ) print("processDownloadedData()") local retval local dataReceived = false if ( event.isError ) then --Hostname not found? else if (event.response == nil) then -- Error - Unknown Error elseif (event.response == "") then -- Error - Unknown Error elseif (IsInString(event.response, "time") == true) then dataReceived = true --Decode temp\_json = nil; temp\_json = json.decode(event.response); elseif (IsInString(event.response, "error") == true) then --unauthorized if (IsInString(event.response, "unauthorized") == true) then retval = native.showAlert( "Error", "Unnauthorized" , { "OK" }, onGenericAlertBox) end end if temp\_json == false then -- No Data. - Thre was no data returned. else -- now do something with the data print("--json-data----------------------------------------------------------------------------") print("time: " .. tostring(temp\_json.time)); print("offset: " .. tostring(temp\_json.milliseconds\_since\_epoch)); print("date: " .. tostring(temp\_json.date)); print("---------------------------------------------------------------------------------------") end end end -- prepare the network request function getJSONData(url, action, in\_json, callback) print("getJSONData()") local json = require ( "json" ) local headers = {} -- headers["Authorization"] = "Basic " .. mime.b64( "username:password" ) headers["Content-Type"] = "application/json" local params = {} params.headers = headers params.body = json.encode( in\_json ) network.request ( url, action, callback, params ) end -- Call the Data (background Call so it wont pause your app) getJSONData("http://date.jsontest.com", "GET", temp\_json, processDownloadedData)
#9

Uncommon the Authorisation line to add username and password to the host headers.

Also add code to check the strong returned, you may get a valid son file but unexpected contents to check the contents.

#10

Thanks mate. I tried this on other websites but it doesn’t seem to be working. My main question is do all websites allow requesting data in JSON format?

Thanks

Amir

#11

All data coming from websites has to be send in the right format. You cant just add “format=json” to the sent URL and expect the server to reconfigure the data on the way out.

#12

Check some of these links out to learn more about JSON.  JSON is my preferred data exchange format over say XML.

http://www.google.com.au/search?safe=active&q=json&oq=json&gs_l=serp.3…1320.1624.0.2008.4.4.0.0.0.0.0.0…0.0.msedr…0…1c.1.64.serp…4.0.0.tXR1A-zC2Qc

#13

No worries mate. I get it now.