optional update statements in diesel using into_boxed() - rust

Question

When I run below code it compiles but it won't update any todo item and affected_rows is equal to 0. What I'm doing wrong here?
Note: I checked official documentation and I didn't find any solution...
pub fn update_todo(req_id: i32, update_payload: TodoUpdate) -> Result<usize, Error>
{
let connection = establish_connection();
let title_payload = match update_payload.title {
Some(title_payload)=> title_payload,
None => "".to_string()
};
let status_payload = match update_payload.status {
Some(status_payload)=> status_payload,
None => "".to_string()
};
let mut query = update(todos)
.set(id.eq(req_id)).into_boxed();
if title_payload.len() > 5 {
query = query.filter(title.eq(title_payload));
}
if status_payload.len() > 3 {
query = query.filter(status.eq(status_payload));
}
query.execute(&connection)
}
Note2: It works fine when I don't use into_boxed() and removing if statements. but I want to work if only title length is greater than 5 and status length greater than 3. It's why I used into_boxed method.

Answer 1

I found the solution. I was doing the whole thing wrong and the right concept is to use AsChangeset in order to update rows in database;
For any one reading this:
The right approach is to use an Option in your structs and derive the AsChangeset alongside table_name like below example:
In this example we have a todo row and we only want to change/update the title of our todo but not changing the status
#[derive(Serialize, Deserialize, AsChangeset)]
#[table_name="todos"]
pub struct TodoUpdate {
pub title: Option<String>,
pub status: Option<String>
}
Now we have to fix handler and add validations! I use match statement to check if there's a value or not and if there was a value inside title I check for it's length otherwise I just ignore it. for example:
match update_payload.title {
Some(ref title_req) => if title_req.len() < 3 {
return HttpResponse::BadRequest().json(json!({
"result": false,
"message": "Title should be at least 3 letter"
}));
},
None => (),
};
match update_payload.status {
Some(ref status_req) => if status_req.len() < 3 {
return HttpResponse::BadRequest().json(json!({
"result": false,
"message": "Status should be at least 3 letter"
}));
},
None => (),
};
After all I call the service I made for updating todos and it's very simple.
pub fn update_todo(req_id: i32, update_payload: TodoUpdate) -> Result<usize, Error>
{
let connection = establish_connection();
diesel::update(todos.filter(id.eq(req_id)))
.set::<TodoUpdate>(update_payload)
.execute(&connection)
}
whew!!! and these codes works fine.. I hope this was helpful for you all.
PS: if you really want to validate user request data you can use actix-web-validator