graphql-client | Typed , correct GraphQL requests and responses in Rust | GraphQL library

If you are not familiar with GraphQL, the official website provides a very good and comprehensive introduction. Once you have written your query (most likely in something like graphiql), save it in a .graphql file in your project. In order to provide precise types for a response, graphql_client needs to read the query and the schema at compile-time. To download the schema, you have multiple options. This projects provides a CLI, however it does not matter what tool you use, the resulting schema.json is the same.
If you are not familiar with GraphQL, the official website provides a very good and comprehensive introduction.
Once you have written your query (most likely in something like graphiql), save it in a .graphql file in your project.
In order to provide precise types for a response, graphql_client needs to read the query and the schema at compile-time. To download the schema, you have multiple options. This projects provides a CLI, however it does not matter what tool you use, the resulting schema.json is the same.
We now have everything we need to derive Rust types for our query. This is achieved through a procedural macro, as in the following snippet: use graphql_client::GraphQLQuery; // The paths are relative to the directory where your `Cargo.toml` is located. // Both json and the GraphQL schema language are supported as sources for the schema #[derive(GraphQLQuery)] #[graphql( schema_path = "tests/unions/union_schema.graphql", query_path = "tests/unions/union_query.graphql", )] pub struct UnionQuery; The derive will generate a module named union_query in this example - the name is the struct's name, but in snake case. That module contains all the struct and enum definitions necessary to deserialize a response to that query. The root type for the response is named ResponseData. The GraphQL response will take the form of a Response<ResponseData> (the Response type is always the same). The module also contains a struct called Variables representing the variables expected by the query.
We now need to create the complete payload that we are going to send to the server. For convenience, the GraphQLQuery trait, is implemented for the struct under derive, so a complete query body can be created this way: use graphql_client::{GraphQLQuery, Response}; use std::error::Error; use reqwest; #[derive(GraphQLQuery)] #[graphql( schema_path = "tests/unions/union_schema.graphql", query_path = "tests/unions/union_query.graphql", response_derives = "Debug", )] pub struct UnionQuery; async fn perform_my_query(variables: union_query::Variables) -> Result<(), Box<dyn Error>> { // this is the important line let request_body = UnionQuery::build_query(variables); let client = reqwest::Client::new(); let mut res = client.post("/graphql").json(&request_body).send().await?; let response_body: Response<union_query::ResponseData> = res.json().await?; println!("{:#?}", response_body); Ok(()) }