> On 13 Dec 2017, at 10:14, Norbert Hartl <norb...@hartl.name> wrote: > > To make your core a little bit more reliable you should not catch the general > error but a NeoJSONParseError. And you need to guard the dictionary access. > There is no guarantee you get something back that inlcudes key success and > message.
Yes, indeed. Also, a better REST API (not something you can change) would not return 200 OK with an error in the payload, but would return a 404 Not Found with a proper error object as payload. FWIW, there are a couple of more sophisticated examples, like in NeoJSONMappingTests and NeoJSONExamplesTests, with comments that do various special cases. > Norbert > > Am 13.12.2017 um 09:54 schrieb Ben Coman <b...@openinworld.com>: > >> hi Sven, >> >> > On 13 Dec 2017, at 07:59, Ben Coman <b...@openinworld.com> wrote: >> > >> > >> > With... >> > Object subclass: #BittrexResponse >> > instanceVariableNames: 'success message result' >> > classVariableNames: '' >> > package: 'Bittrex' >> > >> > Object subclass: #BittrexMarketSummary >> > instanceVariableNames: 'MarketName High Low Volume Last >> > BaseVolume TimeStamp Bid Ask OpenBuyOrders >> > OpenSellOrders PrevDay Created DisplayMarketName' >> > classVariableNames: '' >> > package: 'Bittrex' >> > >> > this code works great when the response holds good data... >> > ZnClient new >> > url: >> > 'https://bittrex.com/api/v1.1/public/getmarketSummary?market=BTC-LTC'; >> > enforceHttpSuccess: true; >> > accept: ZnMimeType applicationJson; >> > contentReader: [ :entity | |reader| >> > reader := (NeoJSONReader on: entity readStream). >> > reader for: BittrexResponse do: [:m| >> > m mapInstVar: #success. >> > m mapInstVar: #message. >> > (m mapInstVar: #result) valueSchema: #ResultArray]. >> > reader for: #ResultArray customDo: [ :mapping | >> > mapping listOfElementSchema: BittrexMarketSummary ]. >> > reader mapInstVarsFor: BittrexMarketSummary. >> > reader nextAs: BittrexResponse ]; >> > get. >> > >> > i.e. a raw response looking like this.... >> > (ZnClient new >> > url: >> > 'https://bittrex.com/api/v1.1/public/getmarketsummary?market=BTC-LTC'; >> > get) inspect. >> > ==> >> > "'{""success"":true,""message"":"",""result"":[{""MarketName"":""BTC-LTC"",""High"":0.01982450,""Low"":0.01285257,""Volume"":1436429.81313360,""Last"":0.01842000,""BaseVolume"":24841.17217724,""TimeStamp"":""2017-12-13T05:56:25.937"",""Bid"":0.01840001,""Ask"":0.01842000,""OpenBuyOrders"":10140,""OpenSellOrders"":6306,""PrevDay"":0.01439800,""Created"":""2014-02-13T00:00:00""}]}'" >> > >> > >> > But for bad response looking like this... >> > (ZnClient new >> > url: >> > 'https://bittrex.com/api/v1.1/public/getmarketsummary?market=INVALID'; >> > get) inspect. >> > ==> {"success":false,"message":"INVALID_MARKET","result":null} >> > >> > the JSON handling code fails deep in the call stack with an error >> > "NeoJSONParseError: [ expected" >> > which is not so friendly for users of the Bittrex library. >> > >> > What are the different/recommended approaches with Zinc >> > for catching JSON errors such that I can pass "message" >> > as a higher level Error up the stack to the Bittrex user. >> > >> > cheers -ben >> >> >> On 13 December 2017 at 15:37, Sven Van Caekenberghe <s...@stfx.eu> wrote: >> BTW, this is no about Zinc, but about NeoJSON. >> >> This is what I meant with variability that is hard to capture with a simple >> static type schema. >> >> I have no time to try myself right now, but a custom mapping for ivar result >> (as in a block) might be able to see the difference and act accordingly. >> >> >> okay. So I played around tracing this through the debugger and for anyone >> else >> with a similar need later, I ended up with the following... >> >> response := (ZnClient new >> url: 'https://bittrex.com/api/v1.1/public/getticker?market=INVALID'; >> enforceHttpSuccess: true; >> accept: ZnMimeType applicationJson; >> contentReader: >> [ :entity | >> [ |reader| >> reader := (NeoJSONReader on: entity readStream). >> reader for: BittrexResponse do: >> [:m| >> m mapInstVar: #success. >> m mapInstVar: #message. >> (m mapInstVar: #result) valueSchema: >> BittrexTicker >> ]. >> reader mapInstVarsFor: BittrexTicker. >> reader nextAs: BittrexResponse >> ] on: Error do: >> [ :err | |json| >> json := NeoJSONReader fromString: entity >> contents. >> (json at: 'success') >> ifFalse: [ self error: (json at: >> 'message') ] >> ifTrue: [ self error: 'UKNOWN ERROR' ] >> ] >> ]) get. >> >> >> for which I get a nice pre-debug window titled "Error: INVALID_MARKET" >> >> cheers -ben >>
