Exploring GraphQL on Android with Apollo

Presentation about GraphQL basics and how to integrate with GraphQL APIs on Android, using the Apollo Client.

Presented at Android DevConference 2017.

1. EXPLORING GRAPHQL WITH APOLLO Ubiratan Soares Agosto / 2017
3. by
6. IS NOT
7. vs
8. WE MUST TALK ABOUT REST
15. REST WAS NOT DESIGNED WITH NOWADAYS APPLICATIONS, DEVICES AND USERS IN MIND …
17. Design Develop Measure API AS PRODUCT
18. KNOW ISSUES FROM REST
19. SCHEMA-LESS
20. VERSIONING
21. MULTIPLE ENDPOINTS TO SOLVE A SPECIFIC NEED FROM CLIENT
22. ENDPOINT EXPOSES MORE DATA THAN CLIENT NEEDS PER HTTP REQUEST
23. MAIN GOALS
24. Single Endpoint “Goodbye" versioning headaches 1
25. Well defined contract Client and server must respect a schema for effective data exchange 2
26. No more overfetching GraphQL clients can fetch only the data they really need for a given purpose 3
27. 4 No more underfetching GraphQL clients can retrieve all the data they need into a single HTTP call : no more chained and/or parallel HTTP requests
28. CORE CONCEPTS
30. TYPE SYSTEM AND SCHEMA
35. Field name != Type name
36. QUERY (IP) LOCDATA city : city location : location LOCATION latitude : String longitude : String time_zone : String CITY geoname_id : String names : cityNames ACCEPTS RETURNS . . . . . . CITYNAMES de : String en : String ru : String . . .
37. QUERIES AND MUTATIONS
38. { getLocation(ip: “172.59.226.170") { country { names { en } geoname_id iso_code } location { latitude longitude } } } Operation Root Query parameter Data that actually matters
39. { getLocation(ip: “172.59.226.170") { country { names { en } geoname_id iso_code } location { latitude longitude } } } "For the available data, return the English name for the country"
40. { getLocation(ip: “172.59.226.170") { country { names { en } geoname_id iso_code } location { latitude longitude } } } "For the available data, return the latitude and the longitude from the geolocation info"
41. { "data": { "getLocation": { "country": { "names": { "en": "Brazil" }, "geoname_id": "3469034", "iso_code": "BR" }, "location": { "latitude": "-23.5733", "longitude": "-46.6417" } } } } QUERY
44. MORE ABOUT OPERATIONS • Data payload will mirror the type hierarchy defined on schema • All data types for queries/mutations must be defined on schema • Operation can accept parameters and/or variables • We can form better, readable blocks for operations using aliases and fragments • Etc
45. CLIENT INTENT REST + HTTP GraphQL + HTTP GraphQL Operation READ RESOURCE GET POST QUERY CREATE RESOURCE POST POST MUTATION UPDATE RESOURCE PUT POST MUTATION REMOVE RESOURCE DELETE POST MUTATION
46. HOW TO USE ON ANDROID ?
49. APOLLO + ANDROID • Full-featured tooling + library, inspired by Retrofit • Custom OkHttpClient support • Code generation for queries / mutations : request models and payloads • Cache-ready client, including L0, L1 e L2 support • RxJava support • Etc
51. PREPARE YOUR QUERY OR MUTATION
52. query LocationQuery ($ip: String!) { getLocation(ip: $ip) { country { names { en } geoname_id iso_code } location { latitude longitude } } } Generated class member To-be-generated class name Operation Type
53. query LocationQuery($ip: String!) { getLocation(ip: $ip) { country { names { en } geoname_id iso_code } location { latitude longitude } } } queryname.graphql
54. RETRIEVE THE ACTUAL SCHEMA
56. > brew install npm
57. > brew install npm > npm install -g apollo-codegen
58. > apollo-codegen download-schema \ https://api.graphloc.com/graphql \ --output schema.json > brew install npm > npm install -g apollo-codegen
59. PROJECT INTEGRATION
60. APPLY PLUGIN AND DEPENDENCIES
61. DEFINE YOUR WORK DIRECTORY
62. Define the package for generated classes Convention DO NOT forget to put schema here
63. class GraphQLAccess { private val apolloClient = ApolloClient .builder() .serverUrl("https://api.graphloc.com/graphql") .build() } // continue ... }
64. fun fetchGeolocation(): Observable<GeolocationInformation> { val ipAddress = "8.8.8.8" val locationQuery = LocationQuery.builder() .ip(ipAddress) .build() val call = apolloClient.query<Data, Data, Variables>(locationQuery) return Rx2Apollo .from<Data>(call) .map { data -> toGeolocationInfo(data, ipAddress) } }
65. fun fetchGeolocation(): Observable<GeolocationInformation> { val ipAddress = "8.8.8.8" val locationQuery = LocationQuery.builder() .ip(ipAddress) .build() val call = apolloClient.query<Data, Data, Variables>(locationQuery) return Rx2Apollo .from<Data>(call) .map { data -> toGeolocationInfo(data, ipAddress) } }
66. fun fetchGeolocation(): Observable<GeolocationInformation> { val ipAddress = "8.8.8.8" val locationQuery = LocationQuery.builder() .ip(ipAddress) .build() val call = apolloClient.query<Data, Data, Variables>(locationQuery) return Rx2Apollo .from<Data>(call) .map { data -> toGeolocationInfo(data, ipAddress) } }
67. fun fetchGeolocation(): Observable<GeolocationInformation> { val ipAddress = "8.8.8.8" val locationQuery = LocationQuery.builder() .ip(ipAddress) .build() val call = apolloClient.query<Data, Data, Variables>(locationQuery) return Rx2Apollo .from<Data>(call) .map { data -> toGeolocationInfo(data, ipAddress) } }
68. private fun toGeolocationInfo( dataResponse: Response<Data>, ipAddress: String): GeolocationInformation { val data = dataResponse.data()?.getLocation val location = data?.location return GeolocationInformation( ip = ipAddress, countryName = data?.country?.names?.en, cityName = data?.city?.names?.en, latitude = location?.latitude, longitutde = location?.longitude, timezone = location?.time_zone ) }
69. private fun toGeolocationInfo( dataResponse: Response<Data>, ipAddress: String): GeolocationInformation { val data = dataResponse.data()?.getLocation val location = data?.location return GeolocationInformation( ip = ipAddress, countryName = data?.country?.names?.en, cityName = data?.city?.names?.en, latitude = location?.latitude, longitutde = location?.longitude, timezone = location?.time_zone ) } Generated by Apollo
70. DONE
71. JUST ADD MORE QUERIES / MUTATIONS AND BE HAPPY !!!
72. FINAL REMARKS
73. FINAL REMARKS • GraphQL is just a spec
74. FINAL REMARKS • GraphQL is just a spec • GraphQL aims to solve some of well know issues from REST
75. FINAL REMARKS • GraphQL is just a spec • GraphQL aims to solve some of well know issues from REST • GraphQL is mobile friendly, but it brings its own set of challenges (for free, rs)
76. FINAL REMARKS • GraphQL is just a spec • GraphQL aims to solve some of well know issues from REST • GraphQL is mobile friendly, but it brings its own set of challenges (for free, rs) • Apollo is an OSS effort for easy integration of GraphQL clients, and it has a full-featured Android native API
77. REFERENCES Oficial GraphQL Website http://graphql.org How to GraphQL https://www.howtographql.com Github Training on GraphQL https://services.github.com/on-demand/graphql Apollo Client for Android - Documentation http://dev.apollodata.com/android
78. https://speakerdeck.com/ubiratansoares
79. UBIRATAN SOARES Computer Scientist by ICMC/USP Software Engineer, curious guy Google Developer Expert for Android Teacher, speaker, etc, etc
80. THANK YOU @ubiratanfsoares ubiratansoares.github.io https://br.linkedin.com/in/ubiratanfsoares