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 ...
};

noctateOP•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

noctateOP•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

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fetching data from external api with trpc