creating a dsl ordering var from String parameters

[greenpdx]

I want to dynamically create an ordering var that I would be able to submit as a query. I am using Postgres and have created a view for a join of two tables. So far so good. I am using jsonrpc-http-server with r2d2 to a Vue frontend. My goal is to create an virtual datatable in vue with sorting.
I can sort locally in the browser, but I want new data from the server to be sorted

Hard coding the ordering works fine. I want to create a dynamic ordering. This will also help me work with other parameters passing. The parts that may be of use are commented out now.

I would like to also help, but my rust is not that good

use jsonrpc_core::*;
use meta::Meta;
use schema;
use diesel::prelude::*;
use diesel::Expression;

#[derive(Deserialize, Debug )]
struct Order {
    pub field: String,
    pub expr: String,
}

#[derive(Deserialize, Debug)]
struct Bye {
    pub start: i32,
    pub limit: i32,
    pub sort: Vec<Order>
}

pub fn methd_bye(params: Params, meta: Meta) -> Result<Value> {
    use self::schema::vidfull::dsl::*;
    use models::VidFull;
    let pool = meta.dbpool;
    let conn = pool.unwrap().pool.get().unwrap();
    println!("{:?}", &params);
    let parm: &Bye = &params.parse().unwrap();
    println!("BYE {:?}", parm);
    let sort = &parm.sort[0];
    let fld = &sort.field;  // String value of field name
    // I will need to loop to handle a multiple order
/*    let ordering: Box<BoxableExpression<fullvid, DB, SqlType=()>> =
        match sort.expr.as_ref() {
            "desc" => fld.desc(),
            "asc" => fld.asc(),
        }; */
    let rslt = vidfull.filter(id.ne(0))
//        .order(())
        .offset(parm.start as i64)
        .limit(parm.limit as i64)
        .load::<VidFull>(&*conn)
        .expect("Error");
    let r = json!(&rslt);

    Ok(Value::String(format!("{}", &r)))
}

Setup

Versions

• **Rust:1.22
• **Diesel: 0.16.0
• **Database:postgres
• **Operating System linux

Feature Flags

• diesel:
• diesel_codegen:

Problem Description

What are you trying to accomplish?

What is the expected output?

What is the actual output?

Are you seeing any additional errors?

Steps to reproduce

Checklist

• I have already looked over the issue tracker for similar issues.

[sgrif]

See #1311 for someone's example of how they are doing dynamic ordering. You can also use the sql function for this.