[Kotlin Serverless 工作坊] 單元 3 - 實作 JSON API
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This document discusses the implementation of a Kotlin serverless API using cloud functions that handle JSON data. It includes details on HTTP requests, response handling, data classes for news articles, and JSON serialization. Examples of API endpoints for fetching news articles are provided, along with instructions on managing GET requests and generating mock data using Java Faker.
![HTTP Response
—
{
"data": [
{
"id": ...,
"title": "...",
"author": "...",
"content": "...",
"coverUrl": "...",
"permalink": "...",
"publishedAt": "..."
},
// ...
]
}
1. n
2. JSON
3. data](https://image.slidesharecdn.com/kotlin-serverless-ep3-json-handling-210423105249/85/Kotlin-Serverless-3-JSON-API-7-320.jpg)
![class Handler: HttpFunction {
@Throws(IOException::class)
override fun service(req: HttpRequest, res: HttpResponse) {
val limit = request.queryParameters["limit"]?
.first()?
.toIntOrNull() ?: 10
}
}
Query
—
• HttpRequest Query
•](https://image.slidesharecdn.com/kotlin-serverless-ep3-json-handling-210423105249/85/Kotlin-Serverless-3-JSON-API-13-320.jpg)
[Kotlin Serverless 工作坊] 單元 3 - 實作 JSON API
- 1. (Shengyou Fan) GDG Taichung 2021/04/17 Cloud Functions Kotlin Serverless API - Ch.3 JSON API - Photo by Jean-Philippe Delberghe on Unsplash
- 2. — • JSON Response • Data Class • JSON Serialization
- 4. HTTP Request — GET http://localhost:8080/getfeed?limit={n} Accept: application/json GET http://localhost:8080/findfeed?id={id} Accept: application/json 1. n 2. JSON 1. id 2. JSON
- 5. class Handler: HttpFunction { @Throws(IOException::class) override fun service(req: HttpRequest, res: HttpResponse) { if ("GET" != request.method.toUpperCase()) { with(response) { setStatusCode(HttpURLConnection.HTTP_BAD_METHOD) writer.write("Bad method") } return } } } HTTP Method —
- 6. class Handler: HttpFunction { @Throws(IOException::class) override fun service(req: HttpRequest, res: HttpResponse) { with(res) { setStatusCode(HttpURLConnection.HTTP_OK) setContentType("application/json") writer.write("...JSON STING...") } } } JSON — • HTTP Status Code • Content-Type •
- 7. HTTP Response — { "data": [ { "id": ..., "title": "...", "author": "...", "content": "...", "coverUrl": "...", "permalink": "...", "publishedAt": "..." }, // ... ] } 1. n 2. JSON 3. data
- 8. Data Class — // Data Class data class News( val id: String, val title: String, val author: String, val content: String, val coverUrl: String? val permalink: String, val publishedAt: String, ) // JSON { "id": 1, "title": "...", "author": "...", "content": "...", "coverUrl": "...", "permalink": "...", "publishedAt": “..." } • JSON Data Class
- 9. // build.gradle plugins { id("...kotlin.plugin.serialization") version "..." } dependencies { implementation("...:kotlinx-serialization-json:$ver") } • Gradle Plugin Serialization — •
- 10. // News @Serializable data class News( // ... ) Annotation —
- 11. val news = (1..10).map { id -> News( // ... ) } —
- 12. Json.encodeToString( mapOf("data" to news) ) JSON — JSON • List Map data • Map JSON
- 13. class Handler: HttpFunction { @Throws(IOException::class) override fun service(req: HttpRequest, res: HttpResponse) { val limit = request.queryParameters["limit"]? .first()? .toIntOrNull() ?: 10 } } Query — • HttpRequest Query •
- 14. Java Faker — • Java Faker // build.gradle dependencies { implementation("com.github.javafaker:javafaker:$ver") }
- 15. val faker = Faker.instance(Locale.TRADITIONAL_CHINESE) News( id = ..., title = faker.lorem().sentence(), author = faker.name().fullName(), content = faker.lorem().paragraph(), coverUrl = "https://${faker.internet().url()}", permalink = "https://${faker.internet().url()}", publishedAt = ..., ) — • Faker