无法解析graphql端点

Question

我正在尝试使用以下代码解析对graphql端点的响应:

extern crate serde_derive;
use gql_client::Client;
use serde::{Deserialize, Serialize};
#[derive(Debug, Serialize, Deserialize)]
pub struct DevActivity {
pub data: Data,
}
#[derive(Debug, Serialize, Deserialize)]
pub struct Data {
#[serde(rename = "getMetric")]
pub get_metric: GetMetric,
}
#[derive(Debug, Serialize, Deserialize)]
pub struct GetMetric {
#[serde(rename = "timeseriesData")]
pub timeseries_data: Vec<TimeseriesDatum>,
}
#[derive(Debug, Serialize, Deserialize)]
pub struct TimeseriesDatum {
pub datetime: String,
pub value: i64,
}
#[derive(Serialize)]
pub struct Vars {
metric: String,
}
#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
let query = r#"
{
getMetric(metric: "dev_activity") {
timeseriesData(slug: "ethereum", from: "2020-02-10T07:00:00Z", to: "2020-03-10T07:00:00Z", interval: "1w") {
datetime
value
}
}
}
"#;
let endpoint = "https://api.santiment.net/graphql";
let client = Client::new(endpoint);
let response = client.query::<DevActivity>(query).await.unwrap().unwrap();
for data in &response.data.get_metric.timeseries_data {
println!("datetime {}, value {}", data.datetime, data.value)
}
Ok(())
}

但是我得到以下错误:

thread 'main' panicked at 'called `Result::unwrap()` on an `Err` value: 
GQLClient Error: Failed to parse response: Error("missing field `data`", line: 1, column: 294). The response body is: {"data":{"getMetric":{"timeseriesData":[{"datetime":"2020-02-06T00:00:00Z","value":795.0},{"datetime":"2020-02-13T00:00:00Z","value":1281.0},{"datetime":"2020-02-20T00:00:00Z","value":1115.0},{"datetime":"2020-02-27T00:00:00Z","value":952.0},{"datetime":"2020-03-05T00:00:00Z","value":605.0}]}}}
', src/main.rs:49:61

我不确定错误是什么，因为我要传递它的结构体有一个data字段

Answer 1

gql_clientcrate代表您解析顶层结构(由data和/或errors组成)。可能是因为它是graphql规范的一部分，您不需要担心它。所以你根本不需要DevActivity结构，只需要使用Data:

let response = client.query::<Data>(query).await.unwrap().unwrap();
for data in &response.get_metric.timeseries_data {
...
}