Create automatic query response unwrapping trait

cli/src/main.rs

@@ -1,6 +1,8 @@
+#![feature(iterator_try_collect)]
+
+use futures::executor::block_on;
 use std::io::{self, Write};
 use std::path::Path;
-use futures::executor::block_on;
 
 mod queries;
 use queries::*;
@@ -24,7 +26,6 @@ fn get_auth_key(config_dir: &Path) -> Option<String> {
     }
 }
 
-
 fn main() {
     let mut config_dir = dirs::config_dir().unwrap();
     config_dir.push("ggelo");
@@ -34,13 +35,16 @@ fn main() {
     let mut search = String::new();
     print!("Search for game: ");
     let _ = io::stdout().flush();
-    io::stdin().read_line(&mut search).expect("Error reading from stdin");
+    io::stdin()
+        .read_line(&mut search)
+        .expect("Error reading from stdin");
 
-    if let Some(response) = block_on(
-            run_query::<VideogameSearch,_>(VideogameSearchVars { name: search }, &auth_key)).data {
-        for maybe_game in response.videogames.unwrap().nodes.unwrap().into_iter() {
-            let game = maybe_game.unwrap();
-            println!("{:?} - {}", game.id.unwrap(), game.name.unwrap());
+    if let Some(response) = block_on(run_query::<VideogameSearch, _>(
+        VideogameSearchVars { name: search },
+        &auth_key,
+    )) {
+        for game in response.into_iter() {
+            println!("{} - {}", game.id, game.name);
         }
     } else {
         println!("No response");

cli/src/queries.rs

@@ -1,22 +1,36 @@
-use cynic::QueryBuilder;
-use serde::{Serialize, Deserialize};
+use std::fmt::{Display, Formatter};
+
+use cynic::{GraphQlResponse, QueryBuilder};
+use serde::{Deserialize, Serialize};
 
 pub mod search_games;
 
 use schema::schema;
 
-/// HACK: Unfortunately, start.gg seems to use integers for its ID type, whereas
-/// cynic always assumes that IDs are strings. To get around that, we define a
-/// new scalar type that serializes to u64.
-#[derive(cynic::Scalar, Debug)]
-pub struct ID(u64);
+// HACK: Unfortunately, start.gg seems to use integers for its ID type, whereas
+// cynic always assumes that IDs are strings. To get around that, we define a
+// new scalar type that serializes to u64.
+#[derive(cynic::Scalar, Debug, Copy, Clone)]
+pub struct ID(pub u64);
 
+impl Display for ID {
+    fn fmt(&self, f: &mut Formatter<'_>) -> core::fmt::Result {
+        <u64 as Display>::fmt(&self.0, f)
+    }
+}
 
-pub async fn run_query<Builder: 'static, Vars>(vars: Vars, auth: &str) -> cynic::GraphQlResponse<Builder>
-    where Builder: QueryBuilder<Vars>,
-          Vars: Serialize,
-          for<'de> Builder: Deserialize<'de>
+pub trait QueryUnwrap<Vars>: QueryBuilder<Vars> {
+    type Unwrapped;
 
+    fn unwrap_response(response: GraphQlResponse<Self>) -> Option<Self::Unwrapped>;
+}
+
+// Generic function for running start.gg queries
+pub async fn run_query<Builder: 'static, Vars>(vars: Vars, auth: &str) -> Option<Builder::Unwrapped>
+where
+    Builder: QueryUnwrap<Vars>,
+    Vars: Serialize,
+    for<'de> Builder: Deserialize<'de>,
 {
     use cynic::http::SurfExt;
 
@@ -27,5 +41,5 @@ pub async fn run_query<Builder: 'static, Vars>(vars: Vars, auth: &str) -> cynic:
         .run_graphql(query)
         .await;
 
-    response.unwrap()
+    <Builder as QueryUnwrap<Vars>>::unwrap_response(response.unwrap())
 }

cli/src/queries/search_games.rs

@@ -1,15 +1,15 @@
-
+use super::{QueryUnwrap, ID};
+use cynic::GraphQlResponse;
 use schema::schema;
-use super::ID;
 
-// VARIABLES
+// Query
 
 #[derive(cynic::QueryVariables)]
 pub struct VideogameSearchVars {
-    pub name: String
+    pub name: String,
 }
 
-// QUERY
+// Query
 
 #[derive(cynic::QueryFragment, Debug)]
 #[cynic(graphql_type = "Query", variables = "VideogameSearchVars")]
@@ -28,3 +28,34 @@ pub struct Videogame {
     pub id: Option<ID>,
     pub name: Option<String>,
 }
+
+// Unwrapping
+
+pub struct VideogameResponse {
+    pub id: ID,
+    pub name: String,
+}
+
+impl QueryUnwrap<VideogameSearchVars> for VideogameSearch {
+    type Unwrapped = Vec<VideogameResponse>;
+
+    fn unwrap_response(
+        response: GraphQlResponse<VideogameSearch>,
+    ) -> Option<Vec<VideogameResponse>> {
+        Some(
+            response
+                .data?
+                .videogames?
+                .nodes?
+                .into_iter()
+                .map(|game| {
+                    let game_ = game?;
+                    Some(VideogameResponse {
+                        id: game_.id?,
+                        name: game_.name?,
+                    })
+                })
+                .try_collect()?,
+        )
+    }
+}