GraphQL API Development in TuskLang with Rust

🎯 GraphQL Foundation

GraphQL with TuskLang and Rust provides a powerful combination for building flexible, type-safe APIs that can efficiently serve complex data requirements. This guide covers schema design, resolvers, and advanced GraphQL patterns.

🏗️ GraphQL Architecture

GraphQL Principles

[graphql_principles]
schema_first: true
type_safety: true
introspection: true
real_time: true
[architecture_patterns]
resolver_pattern: true
data_loader: true
subscriptions: true
federation: true

GraphQL Components

[graphql_components]
schema: "graphql_schema"
resolvers: "field_resolvers"
data_sources: "database_apis"
subscriptions: "real_time_updates"

🔧 GraphQL Schema Design

Schema Definition

[schema_definition]
language: "graphql_sdl"
validation: "schema_validation"
introspection: "enabled"
[schema_implementation]
use async_graphql::{Schema, Object, SimpleObject, InputObject, Enum};
use async_graphql::http::{GraphiQLSource, playground_source};
use async_graphql::ServerError;
#[derive(SimpleObject)]
struct User {
    id: ID,
    email: String,
    name: String,
    status: UserStatus,
    created_at: DateTime<Utc>,
    updated_at: DateTime<Utc>,
}
#[derive(Enum, Copy, Clone, Eq, PartialEq)]
enum UserStatus {
    Active,
    Inactive,
    Suspended,
}
#[derive(InputObject)]
struct CreateUserInput {
    email: String,
    name: String,
    password: String,
}
#[derive(InputObject)]
struct UpdateUserInput {
    name: Option<String>,
    status: Option<UserStatus>,
}
#[derive(SimpleObject)]
struct UserConnection {
    edges: Vec<UserEdge>,
    page_info: PageInfo,
}
#[derive(SimpleObject)]
struct UserEdge {
    node: User,
    cursor: String,
}
#[derive(SimpleObject)]
struct PageInfo {
    has_next_page: bool,
    has_previous_page: bool,
    start_cursor: Option<String>,
    end_cursor: Option<String>,
}

Root Schema

[root_schema]
query: "Query"
mutation: "Mutation"
subscription: "Subscription"
[schema_implementation]
struct Query;
#[Object]
impl Query {
    async fn user(&self, ctx: &Context<'_>, id: ID) -> Result<Option<User>, ServerError> {
        let config = ctx.data::<Config>()?;
        let user_service = ctx.data::<UserService>()?;
        
        user_service.get_user_by_id(&id.to_string()).await
            .map_err(|e| ServerError::new(e.to_string(), None))
    }
    
    async fn users(
        &self,
        ctx: &Context<'_>,
        first: Option<i32>,
        after: Option<String>,
    ) -> Result<UserConnection, ServerError> {
        let config = ctx.data::<Config>()?;
        let user_service = ctx.data::<UserService>()?;
        
        let limit = first.unwrap_or(10).min(100);
        let cursor = after.and_then(|c| base64::decode(c).ok());
        
        let (users, has_next) = user_service.get_users(limit, cursor).await
            .map_err(|e| ServerError::new(e.to_string(), None))?;
        
        let edges: Vec<UserEdge> = users
            .into_iter()
            .map(|user| UserEdge {
                node: user,
                cursor: base64::encode(user.id.to_string()),
            })
            .collect();
        
        Ok(UserConnection {
            edges,
            page_info: PageInfo {
                has_next_page: has_next,
                has_previous_page: false,
                start_cursor: edges.first().map(|e| e.cursor.clone()),
                end_cursor: edges.last().map(|e| e.cursor.clone()),
            },
        })
    }
    
    async fn search_users(
        &self,
        ctx: &Context<'_>,
        query: String,
        filters: Option<UserFilters>,
    ) -> Result<Vec<User>, ServerError> {
        let config = ctx.data::<Config>()?;
        let user_service = ctx.data::<UserService>()?;
        
        user_service.search_users(&query, filters).await
            .map_err(|e| ServerError::new(e.to_string(), None))
    }
}
struct Mutation;
#[Object]
impl Mutation {
    async fn create_user(
        &self,
        ctx: &Context<'_>,
        input: CreateUserInput,
    ) -> Result<User, ServerError> {
        let config = ctx.data::<Config>()?;
        let user_service = ctx.data::<UserService>()?;
        
        user_service.create_user(&input).await
            .map_err(|e| ServerError::new(e.to_string(), None))
    }
    
    async fn update_user(
        &self,
        ctx: &Context<'_>,
        id: ID,
        input: UpdateUserInput,
    ) -> Result<User, ServerError> {
        let config = ctx.data::<Config>()?;
        let user_service = ctx.data::<UserService>()?;
        
        user_service.update_user(&id.to_string(), &input).await
            .map_err(|e| ServerError::new(e.to_string(), None))
    }
    
    async fn delete_user(
        &self,
        ctx: &Context<'_>,
        id: ID,
    ) -> Result<bool, ServerError> {
        let config = ctx.data::<Config>()?;
        let user_service = ctx.data::<UserService>()?;
        
        user_service.delete_user(&id.to_string()).await
            .map_err(|e| ServerError::new(e.to_string(), None))
    }
}

🔄 Resolver Implementation

Field Resolvers

[field_resolvers]
async_resolvers: true
error_handling: true
context_injection: true
[resolver_implementation]
#[Object]
impl User {
    async fn id(&self) -> ID {
        ID(self.id.clone())
    }
    
    async fn email(&self) -> &str {
        &self.email
    }
    
    async fn name(&self) -> &str {
        &self.name
    }
    
    async fn status(&self) -> UserStatus {
        self.status
    }
    
    async fn created_at(&self) -> DateTime<Utc> {
        self.created_at
    }
    
    async fn updated_at(&self) -> DateTime<Utc> {
        self.updated_at
    }
    
    async fn orders(&self, ctx: &Context<'_>) -> Result<Vec<Order>, ServerError> {
        let order_service = ctx.data::<OrderService>()?;
        
        order_service.get_orders_by_user_id(&self.id).await
            .map_err(|e| ServerError::new(e.to_string(), None))
    }
    
    async fn profile(&self, ctx: &Context<'_>) -> Result<Option<UserProfile>, ServerError> {
        let profile_service = ctx.data::<ProfileService>()?;
        
        profile_service.get_profile_by_user_id(&self.id).await
            .map_err(|e| ServerError::new(e.to_string(), None))
    }
}

Data Loaders

[data_loaders]
batch_loading: true
caching: true
n_plus_one_prevention: true
[loader_implementation]
use async_graphql::dataloader::{DataLoader, Loader};
use std::collections::HashMap;
pub struct UserLoader {
    user_service: UserService,
}
#[async_trait::async_trait]
impl Loader<ID> for UserLoader {
    type Value = User;
    type Error = ServerError;
    
    async fn load(&self, keys: &[ID]) -> Result<HashMap<ID, Self::Value>, Self::Error> {
        let user_ids: Vec<String> = keys.iter().map(|id| id.to_string()).collect();
        
        let users = self.user_service.get_users_by_ids(&user_ids).await
            .map_err(|e| ServerError::new(e.to_string(), None))?;
        
        let mut result = HashMap::new();
        for user in users {
            result.insert(ID(user.id.clone()), user);
        }
        
        Ok(result)
    }
}
pub struct OrderLoader {
    order_service: OrderService,
}
#[async_trait::async_trait]
impl Loader<String> for OrderLoader {
    type Value = Vec<Order>;
    type Error = ServerError;
    
    async fn load(&self, user_ids: &[String]) -> Result<HashMap<String, Self::Value>, Self::Error> {
        let orders = self.order_service.get_orders_by_user_ids(user_ids).await
            .map_err(|e| ServerError::new(e.to_string(), None))?;
        
        let mut result = HashMap::new();
        for (user_id, user_orders) in orders {
            result.insert(user_id, user_orders);
        }
        
        Ok(result)
    }
}

🗄️ Database Integration

Database Resolvers

[database_resolvers]
connection_pooling: true
query_optimization: true
transaction_management: true
[database_implementation]
pub struct UserService {
    db: PgPool,
    config: Config,
}
impl UserService {
    pub async fn get_user_by_id(&self, id: &str) -> Result<Option<User>, ServiceError> {
        let user = sqlx::query_as!(
            User,
            r#"
            SELECT id, email, name, status as "status: UserStatus", created_at, updated_at
            FROM users
            WHERE id = $1
            "#,
            id
        )
        .fetch_optional(&self.db)
        .await?;
        
        Ok(user)
    }
    
    pub async fn get_users(&self, limit: i32, cursor: Option<Vec<u8>>) -> Result<(Vec<User>, bool), ServiceError> {
        let mut query = sqlx::QueryBuilder::new(
            r#"
            SELECT id, email, name, status as "status: UserStatus", created_at, updated_at
            FROM users
            "#
        );
        
        if let Some(cursor_data) = cursor {
            query.push(" WHERE id > ");
            query.push_bind(String::from_utf8(cursor_data)?);
        }
        
        query.push(" ORDER BY id LIMIT ");
        query.push_bind(limit + 1);
        
        let mut users: Vec<User> = query.build_query_as().fetch_all(&self.db).await?;
        
        let has_next = users.len() > limit as usize;
        if has_next {
            users.pop();
        }
        
        Ok((users, has_next))
    }
    
    pub async fn create_user(&self, input: &CreateUserInput) -> Result<User, ServiceError> {
        let user = sqlx::query_as!(
            User,
            r#"
            INSERT INTO users (email, name, password_hash, status, created_at, updated_at)
            VALUES ($1, $2, $3, $4, $5, $5)
            RETURNING id, email, name, status as "status: UserStatus", created_at, updated_at
            "#,
            input.email,
            input.name,
            hash_password(&input.password)?,
            UserStatus::Active,
            chrono::Utc::now()
        )
        .fetch_one(&self.db)
        .await?;
        
        Ok(user)
    }
    
    pub async fn update_user(&self, id: &str, input: &UpdateUserInput) -> Result<User, ServiceError> {
        let mut query = sqlx::QueryBuilder::new(
            r#"
            UPDATE users SET
            "#
        );
        
        let mut updates = Vec::new();
        if let Some(name) = &input.name {
            updates.push(("name", name));
        }
        if let Some(status) = &input.status {
            updates.push(("status", &format!("{:?}", status)));
        }
        
        for (i, (field, value)) in updates.iter().enumerate() {
            if i > 0 {
                query.push(", ");
            }
            query.push(field);
            query.push(" = ");
            query.push_bind(value);
        }
        
        query.push(", updated_at = ");
        query.push_bind(chrono::Utc::now());
        query.push(" WHERE id = ");
        query.push_bind(id);
        query.push(
            r#"
            RETURNING id, email, name, status as "status: UserStatus", created_at, updated_at
            "#
        );
        
        let user = query.build_query_as().fetch_one(&self.db).await?;
        Ok(user)
    }
}

🔄 Real-Time Subscriptions

Subscription Implementation

[subscription_implementation]
websocket: true
event_streaming: true
filtering: true
[subscription_schema]
struct Subscription;
#[Object]
impl Subscription {
    async fn user_updated(&self, ctx: &Context<'_>) -> impl Stream<Item = User> {
        let user_service = ctx.data::<UserService>().unwrap();
        user_service.subscribe_to_user_updates().await
    }
    
    async fn order_created(&self, ctx: &Context<'_>, user_id: Option<ID>) -> impl Stream<Item = Order> {
        let order_service = ctx.data::<OrderService>().unwrap();
        order_service.subscribe_to_order_creations(user_id.map(|id| id.to_string())).await
    }
    
    async fn notification_received(&self, ctx: &Context<'_>, user_id: ID) -> impl Stream<Item = Notification> {
        let notification_service = ctx.data::<NotificationService>().unwrap();
        notification_service.subscribe_to_notifications(&user_id.to_string()).await
    }
}
[subscription_service]
pub struct UserService {
    db: PgPool,
    event_sender: tokio::sync::broadcast::Sender<User>,
}
impl UserService {
    pub async fn subscribe_to_user_updates(&self) -> impl Stream<Item = User> {
        let mut receiver = self.event_sender.subscribe();
        
        async_stream::stream! {
            while let Ok(user) = receiver.recv().await {
                yield user;
            }
        }
    }
    
    pub async fn notify_user_update(&self, user: User) -> Result<(), ServiceError> {
        let _ = self.event_sender.send(user);
        Ok(())
    }
}

🔒 Authentication & Authorization

Auth Implementation

[auth_implementation]
jwt_authentication: true
role_based_authorization: true
field_level_security: true
[auth_config]
jwt_secret: "@env.secure('JWT_SECRET')"
jwt_expiry: "24h"
roles: ["admin", "user", "moderator"]
[auth_middleware]
pub struct AuthMiddleware;
impl AuthMiddleware {
    pub async fn authenticate(ctx: &Context<'_>) -> Result<User, ServerError> {
        let token = ctx.data::<Option<String>>()?
            .ok_or_else(|| ServerError::new("No authorization token", None))?;
        
        let user = verify_jwt_token(token).await
            .map_err(|e| ServerError::new(e.to_string(), None))?;
        
        Ok(user)
    }
    
    pub fn require_role(required_role: &str) -> impl Fn(&Context<'_>) -> Result<(), ServerError> {
        let required_role = required_role.to_string();
        move |ctx: &Context<'_>| {
            let user = ctx.data::<User>()?;
            if user.roles.contains(&required_role) {
                Ok(())
            } else {
                Err(ServerError::new("Insufficient permissions", None))
            }
        }
    }
}
[protected_resolvers]
#[Object]
impl Query {
    #[graphql(guard = "AuthMiddleware::require_role(\"admin\")")]
    async fn admin_users(&self, ctx: &Context<'_>) -> Result<Vec<User>, ServerError> {
        let user_service = ctx.data::<UserService>()?;
        user_service.get_all_users().await
            .map_err(|e| ServerError::new(e.to_string(), None))
    }
    
    async fn my_profile(&self, ctx: &Context<'_>) -> Result<User, ServerError> {
        let user = AuthMiddleware::authenticate(ctx).await?;
        Ok(user)
    }
}

📊 Performance Optimization

Query Optimization

[query_optimization]
field_selection: true
query_complexity: true
depth_limiting: true
[optimization_config]
max_complexity: 100
max_depth: 10
query_timeout: "30s"
[complexity_analysis]
pub struct ComplexityAnalyzer;
impl ComplexityAnalyzer {
    pub fn analyze_query(query: &str) -> Result<i32, ServerError> {
        // Implement query complexity analysis
        let complexity = calculate_complexity(query);
        
        if complexity > 100 {
            Err(ServerError::new("Query too complex", None))
        } else {
            Ok(complexity)
        }
    }
}
[depth_limiting]
pub struct DepthLimiter;
impl DepthLimiter {
    pub fn limit_depth(query: &str, max_depth: i32) -> Result<(), ServerError> {
        let depth = calculate_query_depth(query);
        
        if depth > max_depth {
            Err(ServerError::new("Query too deep", None))
        } else {
            Ok(())
        }
    }
}

Caching Strategy

[caching_strategy]
response_caching: true
field_caching: true
cache_invalidation: true
[cache_implementation]
use async_graphql::extensions::CacheControl;
pub struct CacheExtension;
impl CacheExtension {
    pub fn cache_response(ttl: Duration) -> CacheControl {
        CacheControl::new().max_age(ttl.as_secs() as i32)
    }
    
    pub fn cache_field(ttl: Duration) -> CacheControl {
        CacheControl::new().max_age(ttl.as_secs() as i32)
    }
}
[cached_resolvers]
#[Object]
impl User {
    #[graphql(cache_control(max_age = 300))]
    async fn profile(&self, ctx: &Context<'_>) -> Result<Option<UserProfile>, ServerError> {
        let profile_service = ctx.data::<ProfileService>()?;
        
        profile_service.get_profile_by_user_id(&self.id).await
            .map_err(|e| ServerError::new(e.to_string(), None))
    }
}

🔧 Server Implementation

Actix-web Integration

[actix_integration]
server: "actix_web"
websocket: "actix_web_actors"
cors: "enabled"
[server_implementation]
use actix_web::{web, App, HttpServer};
use actix_web::middleware::Logger;
use async_graphql::http::{GraphiQLSource, playground_source};
use async_graphql_actix_web::{GraphQLRequest, GraphQLResponse};
#[actix_web::main]
async fn main() -> std::io::Result<()> {
    let config = tusk_config::load("graphql.tusk")?;
    let schema = create_schema().await;
    
    HttpServer::new(move || {
        App::new()
            .wrap(Logger::default())
            .service(
                web::resource("/graphql")
                    .guard(web::Post())
                    .to(index)
            )
            .service(
                web::resource("/graphiql")
                    .guard(web::Get())
                    .to(|| async { GraphiQLSource::build().endpoint("/graphql").finish() })
            )
            .service(
                web::resource("/playground")
                    .guard(web::Get())
                    .to(|| async { playground_source("/graphql", None) })
            )
            .app_data(web::Data::new(schema.clone()))
            .app_data(web::Data::new(config.clone()))
    })
    .bind(format!("{}:{}", config.host, config.port))?
    .run()
    .await
}
async fn index(
    schema: web::Data<Schema<Query, Mutation, Subscription>>,
    req: GraphQLRequest,
) -> GraphQLResponse {
    schema.execute(req.into_inner()).await.into()
}

TuskLang Configuration

[graphql_tusk_config]
graphql.tusk
[graphql_server]
host: "0.0.0.0"
port: 8080
cors_enabled: true
playground_enabled: true
[graphql_config]
max_complexity: 100
max_depth: 10
query_timeout: "30s"
introspection_enabled: true
[database]
url: "@env('DATABASE_URL')"
pool_size: 20
timeout_seconds: 30
[authentication]
jwt_secret: "@env.secure('JWT_SECRET')"
jwt_expiry: "24h"
refresh_token_expiry: "7d"
[caching]
redis_url: "@env('REDIS_URL')"
response_cache_ttl: "5m"
field_cache_ttl: "1h"
[monitoring]
metrics_enabled: true
tracing_enabled: true
query_logging: true

🎯 Best Practices

1. Schema Design

- Design schema for your use cases - Use descriptive field names - Implement proper error handling - Use input types for mutations

2. Performance

- Implement data loaders - Use field-level caching - Optimize database queries - Monitor query complexity

3. Security

- Implement proper authentication - Use field-level authorization - Validate input data - Rate limit queries

4. Error Handling

- Use proper error types - Provide meaningful error messages - Implement error logging - Handle partial failures

5. Monitoring

- Track query performance - Monitor error rates - Use distributed tracing - Set up alerting

GraphQL with TuskLang and Rust provides a powerful foundation for building flexible, type-safe APIs that can efficiently serve complex data requirements while maintaining excellent performance and developer experience.