Theo's Typesafe Cult•3y ago

fetching data from external api with trpc

So i've watched a couple trpc videos, but I still don't know how to fetch data from some api for example: https://pokeapi.co/ with TRPC. TRPC is for sure the most confusing part of the stack for me. Am I just dumb?

PokéAPI

An open RESTful API for Pokémon data

9 Replies

Matvey•3y ago

You need tRPC on the server to use tRPC on the client. You can't fetch data from a REST API with tRPC Just use Fetch and React Query

Keef•3y ago

Basically what ronan said but you can use trpc to interact with a rest api indirectly In your query/mutation you have to do the async work there which in this case would be doing the fetch*

Matvey•3y ago

You can also proxy the API with a tRPC server

julius•3y ago

You'd just put the fetch call in your procedure:

const pokeApiUrl = "https://pokeapi.co";

export const pokemonRouter = router({
  getByName: publicProcedure
    .input(z.object({ name: z.string() }))
    .query(async ({ input }) => {
      const pokeRes = await fetch(`${pokeApiUrl}/pokemon/${input.name}`);
      // perhaps some error handling
      if (!pokeRes.ok) {
        throw new TRPCError(...);
      }

      // shold prob validate the shape with Zod
      const validated = pokemonValidator.parse(pokeRes.json());
      return validated;
    }),
});

// then on the frontend just call it
const MyComp = () => {
  const pokeQuery = trpc.pokemon.getByName({ name: "zapdos" });

  return ...
};

const pokeApiUrl = "https://pokeapi.co";

export const pokemonRouter = router({
  getByName: publicProcedure
    .input(z.object({ name: z.string() }))
    .query(async ({ input }) => {
      const pokeRes = await fetch(`${pokeApiUrl}/pokemon/${input.name}`);
      // perhaps some error handling
      if (!pokeRes.ok) {
        throw new TRPCError(...);
      }

      // shold prob validate the shape with Zod
      const validated = pokemonValidator.parse(pokeRes.json());
      return validated;
    }),
});

// then on the frontend just call it
const MyComp = () => {
  const pokeQuery = trpc.pokemon.getByName({ name: "zapdos" });

  return ...
};

noctate•3y ago

thx!!! now you advices make sense yours* So adding that, just to help me understand the idea: is fetching the data this way inside a trpc making it server side? Or do I have weird understanding of it? I'm sorry if this is dumb question I just want to understand it enough And how should I choose if I do or I don't need to use trpc in my example? For example if I want to display a filterable table of 100 pokemons which method of rendering I should choose?

julius•3y ago

this way your client fetches your server, then your server fetches the pokemon api you can just do the fetching on the client using react-query (or even swr) if this is the only fetching you'll do

const MyComp = () => {
  const pokeQuery = useQuery(["getPokemon", async () => {
    const pokeRes = await fetch(...);
    ...
  }]);

  return ...
};

const MyComp = () => {
  const pokeQuery = useQuery(["getPokemon", async () => {
    const pokeRes = await fetch(...);
    ...
  }]);

  return ...
};

but if you already have trpc setup its pretty neat to do the fetches from there i think and keeps it clean

noctate•3y ago

Oh okay but if I plan to use trpc for other things some related with users, is it a good idea to keep all fetches in trpc? Oh i see Thx I guess Im starting to to get the idea also another question: what is this? const validated = pokemonValidator.parse

Unknown User•3y ago

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julius•3y ago

Yea you'd make a Zod validator that you can validate the data against. So lets say the API returns something like

{
  data: [
    {
      id: "123",
      name: "zapdos",
      attackPower: 420,
      idk: "whatever",
    },
    ...
  ],
  someOtherMetaData: {}
}

{
  data: [
    {
      id: "123",
      name: "zapdos",
      attackPower: 420,
      idk: "whatever",
    },
    ...
  ],
  someOtherMetaData: {}
}

you'd create your validator smth like this

const PokemonValidator = z.object({
  id: z.string(),
  name: z.string(),
  attackPower: z.number(),
  idk: z.string(),
});
type Pokemon = z.infer<typeof PokemonValidator>;

const responseValidator = z.array(PokemonValidator);

const PokemonValidator = z.object({
  id: z.string(),
  name: z.string(),
  attackPower: z.number(),
  idk: z.string(),
});
type Pokemon = z.infer<typeof PokemonValidator>;

const responseValidator = z.array(PokemonValidator);

and then you can validate the data something like this

const valid = responseValidator.safeParse(res.json().data);
if (!valid.success) {
  console.error(valid.error);
}
// data is valid and typed
return valid.data;

const valid = responseValidator.safeParse(res.json().data);
if (!valid.success) {
  console.error(valid.error);
}
// data is valid and typed
return valid.data;

So then if the API changes its response you'd get validation errors instead of runtime errors which makes it so much easier to debug

Gaming

Programming

fetching data from external api with trpc