Sending requests from Function service

The Function service allows you to send HTTP requests to third-party applications. This enables you to integrate with external services and retrieve data from them.

Currently, sending requests from the Function service to your application on the Tailor Platform is not supported.You can only send requests to external services.

In this guide, we will show you how to send an HTTP request from the Function service using npm packages.

1. Write your function and bundle it for deployment

When you use npm packages in Function service, you need to bundle your function with the packages. In this guide, we use esbuild to bundle your function with npm packages but any bundlers can be used.

Assuming you have a function like below:

import { gql, request } from "graphql-request";

globalThis.main = async function (args) {
  const document = gql`
    query ExampleQuery($pokemon: String!) {
      getFuzzyPokemon(pokemon: $pokemon) {
        species
      }
    }
  `;

  const variables = {
    pokemon: args.pokemon, // e.g., "rayquaza"
  };
  let res = await request("https://graphqlpokemon.favware.tech/v8", document, variables);

  return { species: res.getFuzzyPokemon[0].species };
};

You need to bundle the function with a bundler. In this case, we use esbuild to bundle the function.

esbuild get_pokemon_function.js --bundle --minify --outfile=dist/get_pokemon_function.js

caveat: You have to setup package.json and install the packages before bundling the function.

Once you bundle the function, you can deploy it to Tailor Platform.

2. Deploy your function

Directory Structure

Here's the sample directory structure for an SDK project. In this example, we place the bundled function code in the functions directory.

.
├── tailor.config.ts
├── package.json
├── functions
│   └── get_pokemon_function.js
├── resolvers
│   └── get-pokemon.ts
└── tailordb
    └── ...

Resolver Example

With SDK, the schema definition is inferred from the input/output types. Here's a sample SDK configuration for setting up a resolver that sends HTTP requests:

import { createResolver, t } from "@tailor-platform/sdk";
import { gql, request } from "graphql-request";

export default createResolver({
  name: "getPokemon",
  description: "sample query resolver",
  operation: "query",
  input: {
    pokemon: t.string(),
  },
  body: async (context) => {
    const document = gql`
      query ExampleQuery($pokemon: String!) {
        getFuzzyPokemon(pokemon: $pokemon) {
          species
        }
      }
    `;

    const variables = {
      pokemon: context.input.pokemon,
    };

    const res = await request("https://graphqlpokemon.favware.tech/v8", document, variables);

    return { species: res.getFuzzyPokemon[0].species };
  },
  output: t.object({
    species: t.string().nullable(),
  }),
});

Deployment

Let's deploy the function to Tailor Platform.

npx tailor deploy

Once the deployment is complete, you can send a request to the function. Navigate to your application's GraphQL playground at:

https://{APP_NAME}-{WORKSPACE_HASH}.erp.dev/query

Then, you can run the query in the playground

query {
  getPokemon(input: { pokemon: "ray" }) {
    species
  }
}

you'll get the response like below:

{
  "data": {
    "getPokemon": {
      "species": "rayquaza"
    }
  }
}