NeoJSON extension - easier list handling with NeoJSONPropertyMapping
hi Sven, With NeoJSON I have found several times in handling lists that I need to indirect through #for:customDo: like this...... reader for: ExercismProblems do: [ :mapping | self halt. (mapper mapInstVar: #problems) valueSchema: #ArrayOfProblems ]. reader for: #ArrayOfProblems customDo: [ :mapping | mapper listOfElementSchema: ExercismProblem ]. when I'd really like to be simpler and more concise like this... reader for: ExercismProblems do: [ :mapping | (mapping mapInstVar: #problems) listOfType: Array withElementSchema: ExercismProblem ]. so I'm seeking your feedback on the following hack which facilitates that. (and if I missed something that already makes it simpler) ---------------------------- Object subclass: #NeoJSONPropertyMapping instanceVariableNames: 'propertyName valueSchema getter setter collectionClass' "Added collectionClass" NeoJSONPropertyMapping >> listOfType: aCollectionClass withElementSchema: elementSchema collectionClass := aCollectionClass. valueSchema := elementSchema NeoJSONPropertyMapping >> readObject: anObject from: jsonReader | value | value := collectionClass ifNil: [jsonReader nextAs: valueSchema] "nil by default retains the original behaviour" ifNotNil: [jsonReader nextList: collectionClass of: valueSchema ]. setter value: anObject value: value NeoJSONReader >> nextList: nextListClass of: schema "copied from #nextAs" "Secondary interface to parse JSON. Return a list of objects, each element according to schema." ^ nextListClass streamContents: [ :stream | self parseListDo: [ stream nextPut: (self nextAs: schema) ] ] ---------------------------- Sample data is shown at: https://github.com/bencoman/pharogui-exercism/blob/master/README.md with the following code to access it. Object subclass: #ExercismAPI instanceVariableNames: 'client rawResponse jsonResponse success message result' classVariableNames: 'ApiKey' package: 'Exercism' ExercismAPI class >> configureApiKey: key ApiKey := key. ExercismAPI >> track: trackIdString self path: 'v2/exercises/' , trackIdString. ExercismAPI >> fetchTrack: trackIdString |znclient response| ApiKey ifNil: [ self error: 'ApiKey not configured. See class-side ExcercismAPI' ]. znclient := ZnClient new https; enforceHttpSuccess: true; accept: ZnMimeType applicationJson; host: 'x.exercism.io' . znclient path: 'v2/exercises/' , trackIdString. znclient queryAt: 'key' put: ApiKey. ^ [ response := znclient get ] on: ZnHttpUnsuccessful do: [ :exception | Transcript crShow: exception ] fetchJsonTrack: trackIdString | reader | reader := NeoJSONReader on: (self fetchTrack: trackIdString) readStream. reader for: ExercismProblems do: [ :mapper | (mapper mapInstVar: #problems) listOfType: Array andElementSchema: ExercismProblem ]. ^ reader nextAs: ExercismProblems In Playground... ExercismAPI configureApiKey: 'ec60c50cb50d4ffaa97903d5ebb3d5ff'. (ExercismAPI new fetchJsonTrack: 'go') inspect I'll reset the apikey shortly. You can get a new one from http://exercism.io/account/key. cheers -ben
Hmm, Ben, Did you see NeoJSONCustomMapping's mapping method category ? There you can already find #listOfElementSchema: #listOfType: #listOfType:andElementSchema: as well as #mapWithValueSchema: I am guessing they do what you want, no ? Or am I missing something as well ? Sven
On 16 Jun 2018, at 20:27, Ben Coman <btc@openinworld.com> wrote:
hi Sven,
With NeoJSON I have found several times in handling lists that I need to indirect through #for:customDo: like this......
reader for: ExercismProblems do: [ :mapping | self halt. (mapper mapInstVar: #problems) valueSchema: #ArrayOfProblems ]. reader for: #ArrayOfProblems customDo: [ :mapping | mapper listOfElementSchema: ExercismProblem ].
when I'd really like to be simpler and more concise like this...
reader for: ExercismProblems do: [ :mapping | (mapping mapInstVar: #problems) listOfType: Array withElementSchema: ExercismProblem ].
so I'm seeking your feedback on the following hack which facilitates that. (and if I missed something that already makes it simpler)
---------------------------- Object subclass: #NeoJSONPropertyMapping instanceVariableNames: 'propertyName valueSchema getter setter collectionClass' "Added collectionClass"
NeoJSONPropertyMapping >> listOfType: aCollectionClass withElementSchema: elementSchema collectionClass := aCollectionClass. valueSchema := elementSchema
NeoJSONPropertyMapping >> readObject: anObject from: jsonReader | value | value := collectionClass ifNil: [jsonReader nextAs: valueSchema] "nil by default retains the original behaviour" ifNotNil: [jsonReader nextList: collectionClass of: valueSchema ]. setter value: anObject value: value
NeoJSONReader >> nextList: nextListClass of: schema "copied from #nextAs" "Secondary interface to parse JSON. Return a list of objects, each element according to schema."
^ nextListClass streamContents: [ :stream | self parseListDo: [ stream nextPut: (self nextAs: schema) ] ] ----------------------------
Sample data is shown at: https://github.com/bencoman/pharogui-exercism/blob/master/README.md with the following code to access it.
Object subclass: #ExercismAPI instanceVariableNames: 'client rawResponse jsonResponse success message result' classVariableNames: 'ApiKey' package: 'Exercism'
ExercismAPI class >> configureApiKey: key ApiKey := key.
ExercismAPI >> track: trackIdString self path: 'v2/exercises/' , trackIdString.
ExercismAPI >> fetchTrack: trackIdString |znclient response| ApiKey ifNil: [ self error: 'ApiKey not configured. See class-side ExcercismAPI' ]. znclient := ZnClient new https; enforceHttpSuccess: true; accept: ZnMimeType applicationJson; host: 'x.exercism.io' . znclient path: 'v2/exercises/' , trackIdString. znclient queryAt: 'key' put: ApiKey. ^ [ response := znclient get ] on: ZnHttpUnsuccessful do: [ :exception | Transcript crShow: exception ]
fetchJsonTrack: trackIdString | reader | reader := NeoJSONReader on: (self fetchTrack: trackIdString) readStream. reader for: ExercismProblems do: [ :mapper | (mapper mapInstVar: #problems) listOfType: Array andElementSchema: ExercismProblem ]. ^ reader nextAs: ExercismProblems
In Playground...
ExercismAPI configureApiKey: 'ec60c50cb50d4ffaa97903d5ebb3d5ff'.
(ExercismAPI new fetchJsonTrack: 'go') inspect
I'll reset the apikey shortly. You can get a new one from http://exercism.io/account/key.
cheers -ben
On 17 June 2018 at 02:47, Sven Van Caekenberghe <sven@stfx.eu> wrote:
Hmm, Ben,
Did you see NeoJSONCustomMapping's mapping method category ?
There you can already find #listOfElementSchema: #listOfType:
#listOfType:andElementSchema: as well as #mapWithValueSchema:
Yes. Indeed thats where I copied my selector naming from, although I switched "with" for ''and" NeoJSONPropertyMapping >> listOfType:withElementSchema: However NeoJSONCustomMappings seems only accessible through "reader for: ... customDo: " while instance variable interaction seems only possible using "reader for: ... do:" So it seems NeoJSONCustomMapping lacks #mapAccessor* methods while NeoJSONObjectMapping lacks #listOfType:* methods and "never the twain shall meet". I didn't look closely at #mapWithValueSchema: but its covering tests seem to operate on Dictionaries rather than Arrays.
I am guessing they do what you want, no ? Or am I missing something as well ?
Yes, but how to mix those list* methods with poking the result into an instance variable to be able to "assign a list of elements to an instance variable" as a one liner? I'd be glad to be shown another way to do this for the given data. I see a few #testLists examples, but none that assign the result to an instance variable. NeoJSONExamplesTests has some "lists of objects" tests, but no "objects with lists" A useful example would be #testPolygonPoints... NeoJSONExamplesTests >> testPolygonPoints | polygon polygonJson result | polygon := Polygon new vertices: { 1@2. 3@4. 5@6 }. polygonJson := '{ "vertices": [ "I'm not clear on how to do the writer side of things" { "x" : 1, "y" : 2 }, { "x" : 3, "y" : 4 }, { "x" : 5, "y" : 6 }] }'. result := (NeoJSONReader on: polygonJson readStream) mapInstVarsFor: Point; for: Polygon do: [ :mapping | (mapping mapInstVar: #vertices) listOfType: Array withElementSchema: Point]; nextAs: Polygon. self assert: result equals: polygon Some equality support is needed for Polygon (PathShape) (my best guess, discussion of this might be worth a separate thread) PathShape >> = aPathShape |otherVertices equal| otherVertices := aPathShape vertices. (self species = aPathShape species) & (vertices size = otherVertices size) ifFalse: [ ^false ]. 1 to: vertices size do: [ :i | (vertices at: i) = (otherVertices at: i) ifFalse: [^false] ]. ^true PathShape >> hash |hash| hash := 0. 1 to: vertices size do: [ :i | hash bitXor: (vertices at: i) ]. ^hash cheers -ben
Sven
On 16 Jun 2018, at 20:27, Ben Coman <btc@openinworld.com> wrote:
hi Sven,
With NeoJSON I have found several times in handling lists that I need to indirect through #for:customDo: like this......
reader for: ExercismProblems do: [ :mapping | self halt. (mapper mapInstVar: #problems) valueSchema: #ArrayOfProblems ]. reader for: #ArrayOfProblems customDo: [ :mapping | mapper listOfElementSchema: ExercismProblem ].
when I'd really like to be simpler and more concise like this...
reader for: ExercismProblems do: [ :mapping | (mapping mapInstVar: #problems) listOfType: Array withElementSchema: ExercismProblem ].
so I'm seeking your feedback on the following hack which facilitates that. (and if I missed something that already makes it simpler)
cheers -ben
participants (2)
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Ben Coman -
Sven Van Caekenberghe