Diesel: Diesel_derives only considers flags comming from one of multiple `#[diesel(…)]` atttributes

[dawid-nowak]

Is it supported at the moment to have 'serialize_as' and 'deserialize_as' on the single field in the sturcture as shown below?

#[derive(Identifiable, Queryable, PartialEq, Debug, Serialize, Deserialize, Insertable)]
#[table_name = "blah"]
pub struct Data {

    #[diesel(serialize_as = "SensitiveStringSerializer")]   
    #[diesel(deserialize_as = "SensitiveStringDeserializer")]

    pub sensitive_data: String
}

[weiznich]

As the documentation mentions here deserialize_as is supported for the Queryable derive. serialize_as is not supported on any release yet.

Closed as this is not an issue or feature request. Use our gitter channel or our forum to ask for support or tho get answers to your questions.

[dawid-nowak]

@weiznich
I do appreciate the prompt reply. The '''serialize_as''' is on the master branch. The issue is that only one of these annotations seems to be working at a time. I can either '''serialize_as''' or '''desrilalize_as''' but not both. In my opinion, that would be a bug, but I thought it might have been nice to doublecheck.

[weiznich]

@dawid-nowak I that case I would appreciate getting a complete self contained example where you think something does not work as expected including the exact version you've used. Otherwise I do not see how this would be actionable at all.

[dawid-nowak]

@weiznich
i hope this helps

#[macro_use]
extern crate diesel;
extern crate dotenv;
extern crate log;
mod schema;
use serde::{Deserialize, Serialize};
use log::info;
use std::io::Write;
use diesel::prelude::*;
use dotenv::dotenv;
use schema::*;
use std::env;
use diesel::{
    backend::Backend,
    deserialize::{
    Queryable,
    FromSql,
    FromSqlRow
    },
    expression::AsExpression,
    serialize::{ToSql, Output, self},
    sql_types,
};

#[derive(Debug, FromSqlRow, AsExpression)]
#[sql_type = "sql_types::Text"]
pub struct SensitiveStringSerializer(pub String);

impl Into<SensitiveStringSerializer> for String {
    fn into(self) -> SensitiveStringSerializer {
        SensitiveStringSerializer(self)
    }
}

impl<DB> ToSql<sql_types::Text, DB> for SensitiveStringSerializer
    where
        DB: Backend,
        String: ToSql<sql_types::Text, DB>,
{
    fn to_sql<W: Write>(&self, out: &mut Output<W, DB>) -> serialize::Result {
    let mut s = self.0.clone();
    s.replace_range(2..s.len()-2,"xxxxx");
    info!("Writing Sensitive string {}",s);
        s.to_sql(out)
    }
}


#[derive(Debug,  AsExpression)]
pub struct SensitiveStringDeserializer(String);

impl<DB, ST> Queryable<ST, DB> for SensitiveStringDeserializer
where
    DB: Backend,
    String: Queryable<ST, DB>,
{
    type Row = <String as Queryable<ST, DB>>::Row;

    fn build(row: Self::Row) -> Self {
    let mut s = String::build(row);
    s.replace_range(2..s.len()-2,"ooooo");
    info!("Reading Sensitive string {}",s);
        SensitiveStringDeserializer(s)
    }
}


impl Into<String> for SensitiveStringDeserializer {
    fn into(self) -> String {
        self.0
    }
}

#[derive(Identifiable, Queryable, PartialEq, Debug, Serialize, Deserialize, Insertable)]
#[table_name = "users"]
pub struct User {
    pub id: i32,

    #[diesel(serialize_as = "SensitiveStringSerializer")]   
    #[diesel(deserialize_as = "SensitiveStringDeserializer")]
    pub s1: String,

    #[diesel(deserialize_as = "SensitiveStringDeserializer")]    
    #[diesel(serialize_as = "SensitiveStringSerializer")]    
    pub s2: String,

    #[diesel(serialize_as = "SensitiveStringSerializer")]    
    pub s3: String,

    #[diesel(deserialize_as = "SensitiveStringDeserializer")]        
    pub s4: String,    
}

fn main() {
    env_logger::init();    
    dotenv().ok();
    let database_url = env::var("DATABASE_URL").expect("DATABASE_URL must be set");
    let conn = PgConnection::establish(&database_url).unwrap_or_else(|_| panic!("Error connecting to {}", database_url));
    let id = 7;
    let u1 = User{
    id,
    s1: "11111111111111111111".to_string(),
    s2: "22222222222222222222".to_string(),
    s3: "33333333333333333333".to_string(),
    s4: "44444444444444444444".to_string(), 
    };
    info!("u1 {:?}",u1);
    diesel::insert_into(schema::users::table).values(u1).execute(&conn).unwrap();
    info!("insert done");
    let u2 = schema::users::dsl::users.find(id).get_result::<User>(&conn).unwrap();
    info!("u2 {:?}",u2);       
}

expected is that User(s1:11111111, s2:22222222, s3:3333333,s4:444444444) will be written to database as User(s1:11xxxx11,s2:22xxxxxx22, s3: 33xxxxxx33, s4: 44444444).

expected is that on read User should be as follows User(s1:11oooooo11,s2:22ooooo22, s3: 33xxxxxxx33, s4: 44ooooooo44).

database view snapshot:

schema:
up.sql

CREATE TABLE users (
  id integer PRIMARY KEY,
  s1 VARCHAR NOT NULL,
  s2 VARCHAR NOT NULL,
  s3 VARCHAR NOT NULL,
  s4 VARCHAR NOT NULL

);

Cargo.toml

[package]
name = "diesel-problem"
version = "0.1.0"
edition = "2018"

[dependencies]  
diesel = { git = "https://github.com/diesel-rs/diesel", branch = "master", features = ["postgres"] }
dotenv = "0.15.0"
serde = { version = "1.0", features = ["derive"] }
serde_derive = "1.0"
serde_json = "1.0"
log = "0.4"
env_logger="0.8"

exact version
diesel v2.0.0 (https://github.com/diesel-rs/diesel?branch=master#daf1d331)

[weiznich]

So I had a short look at this. Seems like we don't handle the case that some attribute occurs more than once well. If you change your code to the following everything will work fine:

#[derive(Identifiable, Queryable, PartialEq, Debug, Serialize, Deserialize, Insertable)]
#[table_name = "users"]
pub struct User {
    pub id: i32,

    #[diesel(serialize_as = "SensitiveStringSerializer", deserialize_as = "SensitiveStringDeserializer")]   
    pub s1: String,

    #[diesel(deserialize_as = "SensitiveStringDeserializer", serialize_as = "SensitiveStringSerializer")]    
    pub s2: String,

    #[diesel(serialize_as = "SensitiveStringSerializer")]    
    pub s3: String,

    #[diesel(deserialize_as = "SensitiveStringDeserializer")]        
    pub s4: String,    
}

(Note that I've changed just fields 1 and 2 to have the annotations in a combined attribute instead of having separate ones.)

Having said that: This is definitively something I would consider as bug, therefore I will reopen the issue. For the next time: Just fill out the issue template as it asks for most of the information required to reproduce nearly all bugs.

For anyone willing to look into fixing this: We would need change this function to not only return the first attribute with matching name, but all. That implies that we need to find a way to merge flags provided by multiple attributes + decide how to handle duplicated flags there.

[dawid-nowak]

now we are talking :) cheers

[pksunkara]

I actually had this fixed in my branch of moving all attributes to diesel. I just need to finish it.

[pksunkara]

That branch is blocked on #2557 which I will finish off first.