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0

I have a variable that gets initialized in main (line 9) and I want to access a reference to this variable inside of one of my route handlers.

#[get("/")]
fn index() -> String 
 return fetch_data::fetch(format!("posts"), &redis_conn).unwrap(); // How can I get redis_conn?


fn main() 
 let redis_conn = fetch_data::get_redis_connection(); // initialized here

 rocket::ignite().mount("/", routes![index]).launch();

In other languages, this problem would be solvable by using global variables.

rust rust-rocket

share|improve this question

edited Mar 27 at 19:09

Shepmaster

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asked Mar 27 at 18:27

MaxMax

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add a comment | 

0

I have a variable that gets initialized in main (line 9) and I want to access a reference to this variable inside of one of my route handlers.

#[get("/")]
fn index() -> String 
 return fetch_data::fetch(format!("posts"), &redis_conn).unwrap(); // How can I get redis_conn?


fn main() 
 let redis_conn = fetch_data::get_redis_connection(); // initialized here

 rocket::ignite().mount("/", routes![index]).launch();

In other languages, this problem would be solvable by using global variables.

rust rust-rocket

share|improve this question

edited Mar 27 at 19:09

Shepmaster

177k2222 gold badges392392 silver badges555555 bronze badges

asked Mar 27 at 18:27

MaxMax

1121212 bronze badges

add a comment | 

I have a variable that gets initialized in main (line 9) and I want to access a reference to this variable inside of one of my route handlers.

#[get("/")]
fn index() -> String 
 return fetch_data::fetch(format!("posts"), &redis_conn).unwrap(); // How can I get redis_conn?


fn main() 
 let redis_conn = fetch_data::get_redis_connection(); // initialized here

 rocket::ignite().mount("/", routes![index]).launch();

In other languages, this problem would be solvable by using global variables.

rust rust-rocket

share|improve this question

edited Mar 27 at 19:09

Shepmaster

177k2222 gold badges392392 silver badges555555 bronze badges

asked Mar 27 at 18:27

MaxMax

1121212 bronze badges

#[get("/")]
fn index() -> String 
 return fetch_data::fetch(format!("posts"), &redis_conn).unwrap(); // How can I get redis_conn?


fn main() 
 let redis_conn = fetch_data::get_redis_connection(); // initialized here

 rocket::ignite().mount("/", routes![index]).launch();

share|improve this question

edited Mar 27 at 19:09

Shepmaster

177k2222 gold badges392392 silver badges555555 bronze badges

asked Mar 27 at 18:27

MaxMax

1121212 bronze badges

share|improve this question

edited Mar 27 at 19:09

Shepmaster

177k2222 gold badges392392 silver badges555555 bronze badges

asked Mar 27 at 18:27

MaxMax

1121212 bronze badges

edited Mar 27 at 19:09

Shepmaster

177k2222 gold badges392392 silver badges555555 bronze badges

edited Mar 27 at 19:09

Shepmaster

177k2222 gold badges392392 silver badges555555 bronze badges

asked Mar 27 at 18:27

MaxMax

1121212 bronze badges

asked Mar 27 at 18:27

MaxMax

1121212 bronze badges

1 Answer
1

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oldest

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1

Please read the Rocket documentation, specifically the section on state.

Use State and Rocket::manage to have shared state:

#![feature(proc_macro_hygiene, decl_macro)]

#[macro_use]
extern crate rocket; // 0.4.2

use rocket::State;

struct RedisThing(i32);

#[get("/")]
fn index(redis: State<RedisThing>) -> String 
 redis.0.to_string()


fn main() 
 let redis = RedisThing(42);

 rocket::ignite()
 .manage(redis)
 .mount("/", routes![index])
 .launch();

If you want to mutate the value inside the State, you will need to wrap it in a Mutex or other type of thread-safe interior mutability.

See also:

• Compiler says that data cannot be shared between threads safely even though the data is wrapped within a Mutex


• Need holistic explanation about Rust's cell and reference counted types


• Share i32 mutably between threads

this problem would be solvable by using global variables.

See also:

• How do I create a global, mutable singleton?

share|improve this answer

edited Aug 21 at 17:22

answered Mar 27 at 18:52

ShepmasterShepmaster

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add a comment | 

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1

Please read the Rocket documentation, specifically the section on state.

Use State and Rocket::manage to have shared state:

#![feature(proc_macro_hygiene, decl_macro)]

#[macro_use]
extern crate rocket; // 0.4.2

use rocket::State;

struct RedisThing(i32);

#[get("/")]
fn index(redis: State<RedisThing>) -> String 
 redis.0.to_string()


fn main() 
 let redis = RedisThing(42);

 rocket::ignite()
 .manage(redis)
 .mount("/", routes![index])
 .launch();

If you want to mutate the value inside the State, you will need to wrap it in a Mutex or other type of thread-safe interior mutability.

See also:

• Compiler says that data cannot be shared between threads safely even though the data is wrapped within a Mutex


• Need holistic explanation about Rust's cell and reference counted types


• Share i32 mutably between threads

this problem would be solvable by using global variables.

See also:

• How do I create a global, mutable singleton?

share|improve this answer

edited Aug 21 at 17:22

answered Mar 27 at 18:52

ShepmasterShepmaster

177k2222 gold badges392392 silver badges555555 bronze badges

add a comment | 

1

Please read the Rocket documentation, specifically the section on state.

Use State and Rocket::manage to have shared state:

#![feature(proc_macro_hygiene, decl_macro)]

#[macro_use]
extern crate rocket; // 0.4.2

use rocket::State;

struct RedisThing(i32);

#[get("/")]
fn index(redis: State<RedisThing>) -> String 
 redis.0.to_string()


fn main() 
 let redis = RedisThing(42);

 rocket::ignite()
 .manage(redis)
 .mount("/", routes![index])
 .launch();

If you want to mutate the value inside the State, you will need to wrap it in a Mutex or other type of thread-safe interior mutability.

See also:

• Compiler says that data cannot be shared between threads safely even though the data is wrapped within a Mutex


• Need holistic explanation about Rust's cell and reference counted types


• Share i32 mutably between threads

this problem would be solvable by using global variables.

See also:

• How do I create a global, mutable singleton?

share|improve this answer

edited Aug 21 at 17:22

answered Mar 27 at 18:52

ShepmasterShepmaster

177k2222 gold badges392392 silver badges555555 bronze badges

add a comment | 

Please read the Rocket documentation, specifically the section on state.

Use State and Rocket::manage to have shared state:

#![feature(proc_macro_hygiene, decl_macro)]

#[macro_use]
extern crate rocket; // 0.4.2

use rocket::State;

struct RedisThing(i32);

#[get("/")]
fn index(redis: State<RedisThing>) -> String 
 redis.0.to_string()


fn main() 
 let redis = RedisThing(42);

 rocket::ignite()
 .manage(redis)
 .mount("/", routes![index])
 .launch();

If you want to mutate the value inside the State, you will need to wrap it in a Mutex or other type of thread-safe interior mutability.

See also:

• Compiler says that data cannot be shared between threads safely even though the data is wrapped within a Mutex


• Need holistic explanation about Rust's cell and reference counted types


• Share i32 mutably between threads

this problem would be solvable by using global variables.

See also:

• How do I create a global, mutable singleton?

share|improve this answer

edited Aug 21 at 17:22

answered Mar 27 at 18:52

ShepmasterShepmaster

177k2222 gold badges392392 silver badges555555 bronze badges

#![feature(proc_macro_hygiene, decl_macro)]

#[macro_use]
extern crate rocket; // 0.4.2

use rocket::State;

struct RedisThing(i32);

#[get("/")]
fn index(redis: State<RedisThing>) -> String 
 redis.0.to_string()


fn main() 
 let redis = RedisThing(42);

 rocket::ignite()
 .manage(redis)
 .mount("/", routes![index])
 .launch();

share|improve this answer

edited Aug 21 at 17:22

answered Mar 27 at 18:52

ShepmasterShepmaster

177k2222 gold badges392392 silver badges555555 bronze badges

answered Mar 27 at 18:52

ShepmasterShepmaster

177k2222 gold badges392392 silver badges555555 bronze badges

answered Mar 27 at 18:52

ShepmasterShepmaster

177k2222 gold badges392392 silver badges555555 bronze badges