feat: Add proxy connection type

[langyo]

PR Info

• Closes Add the proxy connection type. #1875

New Features

• Add the proxy connection type.

Changes

• Add a new feature called proxy.
• GIve a demo to help us create a proxy connection quickly.

[langyo]

Although the test samples and example code are not rich enough, I think it is time to start reviewing the code.

If it can be merged, I'll do some additional work, such as adding CI configuration and writing more examples.

[langyo]

cc @tyt2y3 😉

[langyo]

This position temporarily disables sqlx because rustls, the upstream dependency of sqlx, cannot compile to any wasm target for the time being. The mainly cause is that rustls-dependent rings need to cross-compile code from C language.

Recently, ring may support compilation of the wasm platform by compiling old cipher suites with BoringC instead, but this will take a long time.

[langyo]

Related to briansmith/ring#1745 and rustls/rustls#521

[langyo]

Now it's ready for review.

Here are three examples that utilize a proxy connection.

The example that utilizes SurrealDB might be able to enhance its robustness by employing the SQL parser, but it doesn't actually matter.

The other example, which uses Wasmtime, relies on the unstable WASI preview support, so its ABI may change in the future.

The third example, which employs GlueSQL, is currently using the legacy version (0.13) to avoid conflicts with the chrono library. Once the conflict is resolved, we can upgrade to the latest version (0.14).

@tyt2y3 😉

[langyo]

I've written a demo for my own project that uses this fork branch, take a look.

[tyt2y3]

That's very interesting indeed. Can you explain how to implement a ProxyDb?

celestia-island/tairitsu@f819768#diff-0f845934140e261f65d6abe821a10b9c11c6f84b68d9ab05aa3e81325dfa2fbb

And indeed how does GlueSQL come into play? How many features of SeaORM is usuable with GlueSQL?

I think it'd be better if we include an example implementation of ProxyDb as well.

[langyo]

That's very interesting indeed. Can you explain how to implement a ProxyDb?

celestia-island/tairitsu@f819768#diff-0f845934140e261f65d6abe821a10b9c11c6f84b68d9ab05aa3e81325dfa2fbb

And indeed how does GlueSQL come into play? How many features of SeaORM is usuable with GlueSQL?

I think it'd be better if we include an example implementation of ProxyDb as well.

The best practices for this are all included in the examples I attached to this fork:

https://github.com/langyo/sea-orm/tree/proxy-conn/examples/proxy_gluesql_example

https://github.com/langyo/sea-orm/tree/proxy-conn/examples/proxy_surrealdb_example

https://github.com/langyo/sea-orm/tree/proxy-conn/examples/proxy_wasmtime_example

It was already done two weeks ago...

To implement a basic proxy database, you only need to prepare a class that implements sea_orm::ProxyDatabaseTrait, and at least implement the query and execute functions. When creating a database later, use the sea_orm::Database::connect_proxy function instead of sea_orm::Database::connect function creation.

By the way, don’t forget to enable the proxy feature.

Here is an example:

struct ProxyDb {}

impl ProxyDatabaseTrait for ProxyDb {
    fn query(&self, statement: Statement) -> Result<Vec<ProxyRow>, DbErr> {
        // ...

        Ok(vec![])
    }

    fn execute(&self, statement: Statement) -> Result<ProxyExecResult, DbErr> {
        // ...

        Ok(ProxyExecResult {
            last_insert_id: 1,
            rows_affected: 1,
        })
    }
}

fn main() -> anyhow::Result<()> {
    let db = Database::connect_proxy(
        DbBackend::Sqlite,
        Arc::new(Mutex::new(Box::new(ProxyDb { }))),
    )
    .await?;

    Ok(())
}

For database engines that are not adapted to the protocols of MySQL, PostgreSQL and Sqlite (such as GlueSQL and SurrealDB), it is necessary to manually re-parse and construct SQL statements. After all, the SQL statements produced by SQLX cannot be used directly...

I am actually planning to introduce a new mechanism to be able to choose other database back-end engines besides SQLX, which includes constructing one on site, but this obviously should be solved by opening another PR.

So...I would do this first. I will implement the feature of the proxy database first, and I will open a new issue to implement the rest later. The current examples for SurrealDB and GlueSQL focus on demonstrating the capabilities of using proxy databases, rather than putting them into production immediately.

[tyt2y3]

Thank you for your explanation! I will read again and then probably merge it as is, if you wouldn't mind becoming the PIC of this feature. TBH I am not 100% clear of your big picture, but I am sure you are making something interesting and great! Let's see how it goes.

[langyo]

Thank you for your explanation! I will read again and then probably merge it as is, if you wouldn't mind becoming the PIC of this feature. TBH I am not 100% clear of your big picture, but I am sure you are making something interesting and great! Let's see how it goes.

Certainly! I appreciate your trust, and I'm glad to continue maintaining the feature if I have free time.

[tyt2y3]

I will make a few edits on the proxy branch

[github-actions]

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