Validating Request Bodies | Effect Http Client

If you want to validate your request body with a Schema before sending it, you can use HttpClientRequest.schemaBodyJson().

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import {
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  FetchHttpClient,
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  HttpClient,
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  HttpClientRequest,
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} from "effect/unstable/http";
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import { Effect, Schema } from "effect";
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const AddRecipeBody = Schema.Struct({
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  name: Schema.String,
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  ingredients: Schema.Array(Schema.String),
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  prepTimeMinutes: Schema.Number,
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  cookTimeMinutes: Schema.Number,
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  servings: Schema.Number,
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});
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function addRecipe(recipe: typeof AddRecipeBody.Type) {
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  return Effect.gen(function* () {
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    const client = yield* HttpClient.HttpClient;
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    const request = yield* HttpClientRequest.post(
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      "https://dummyjson.com/recipes/add",
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    ).pipe(HttpClientRequest.schemaBodyJson(AddRecipeBody)(recipe));
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    const response = yield* client.execute(request);
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    const data = yield* response.json;
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    return data;
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  }).pipe(Effect.provide(FetchHttpClient.layer));
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}
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// Test it
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Effect.runPromise(
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  addRecipe({
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    name: "Masala Chai",
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    ingredients: ["black tea", "milk", "ginger", "cardamom", "sugar"],
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    prepTimeMinutes: 5,
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    cookTimeMinutes: 10,
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    servings: 2,
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  }),
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).then((data) => {
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  console.log("Created recipe:", data);
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});

Output:

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Created recipe: {
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  id: 51,
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  name: 'Masala Chai',
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  ingredients: [ 'black tea', 'milk', 'ginger', 'cardamom', 'sugar' ],
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  prepTimeMinutes: 5,
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  cookTimeMinutes: 10,
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  servings: 2
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}

schemaBodyJson is a curried function. You first pass the schema, then the data:

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HttpClientRequest.schemaBodyJson(AddRecipeBody)(recipe);
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//                                ^^^^^^^^^^^^  ^^^^^^
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//                                   schema      data

This returns an Effect<HttpClientRequest, HttpBodyError>, which is why the request is created with yield* instead of being assigned directly..

Note that the schema validates your data before it’s serialized to JSON. If the data doesn’t match, you get a SchemaError in the error channel. The request is never sent. This catches bugs at the point of construction rather than at the server.

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