AqlQuery with bind_vars

[inzanez]

Hi

How is one supposed to be using bind_vars? Using the web-query-builder from ArangoDB, I'm used to being able to create queries as follows:
INSERT @user INTO @@collection with user: { "name": "Test" } and @collection: "users".

Assuming I tried the same with the query builder, I tried:

const COLLECTION: &str = "users";

#[derive(Serialize)]
pub struct User {
    name: String,
}

fn main() {
    let user = User { name: "Tester".to_string() };
    let conn = Connection::establish_jwt("http://localhost:8529", "root", "Password")
        .unwrap();

    let db = conn.db("Test").unwrap();

    let json = serde_json::to_string(&user).unwrap();
    let aql = AqlQuery::builder()
        .query("INSERT @user INTO @@collection LET result = NEW RETURN result")
        .bind_var("@collection", COLLECTION)
        .bind_var("user", json)
        .build();

    let result: Vec<Value> = db.aql_query(aql).expect("Query failed");
}

However, that fails, as the query generated escapes the double quotes in the JSON that I generated. Resulting in this:
{"query":"INSERT @client INTO @@collection LET result = NEW RETURN result","bindVars":{"client":"{\"name\":\"Tester\"}","@collection":"fs_clients" }

instead of this
{"query":"INSERT @client INTO @@collection LET result = NEW RETURN result","bindVars":{"client":"{"name":"Tester"}","@collection":"fs_clients" }

If I tried assigning the user struct directly however:

const COLLECTION: &str = "users";

#[derive(Serialize)]
pub struct User {
    name: String,
}

fn main() {
    let user = User { name: "Tester".to_string() };
    let conn = Connection::establish_jwt("http://localhost:8529", "root", "Password")
        .unwrap();

    let db = conn.db("Test").unwrap();

    let aql = AqlQuery::builder()
        .query("INSERT @user INTO @@collection LET result = NEW RETURN result")
        .bind_var("@collection", COLLECTION)
        .bind_var("user", user)
        .build();

    let result: Vec<Value> = db.aql_query(aql).expect("Query failed");
}

I cannot compile, as:
^^^^^^^^ the trait 'std::convert::From<User>' is not implemented for 'serde_json::value::Value'

[arn-the-long-beard]

Hello!!

Thank you for your post !

Yeah it seems we have something weird there.

Let ' me write an example with a PR and I come back to you, sounds good for you ?

[inzanez]

Well, yes, and thanks for the answer! But I think I figured it out:

const COLLECTION: &str = "users";

#[derive(Serialize)]
pub struct User {
    name: String,
}

fn main() {
    let user = User { name: "Tester".to_string() };
    let conn = Connection::establish_jwt("http://localhost:8529", "root", "Password")
        .unwrap();

    let db = conn.db("Test").unwrap();

    let json = serde_json::to_value(&user).unwrap();
    let aql = AqlQuery::builder()
        .query("INSERT @user INTO @@collection LET result = NEW RETURN result")
        .bind_var("@collection", COLLECTION)
        .bind_var("user", json)
        .build();

    let result: Vec<Value> = db.aql_query(aql).expect("Query failed");
}

So convert the struct to a serde_json::value::Value, not a string! Now it works.

let json = serde_json::to_value(&user).unwrap();

[arn-the-long-beard]

Hoo mate thank you 👍

I had the same issue as you actually. Thank you for your response. I PR an example so people know where to look in the future !

[arn-the-long-beard]

Do you still have this issue by the way ?

However, that fails, as the query generated escapes the double quotes in the JSON that I generated. Resulting in this:
{"query":"INSERT @client INTO @@collection LET result = NEW RETURN result","bindVars":{"client":"{"name":"Tester"}","@collection":"fs_clients" }

[fMeow]

You could assign the user struct directly by using try_bind instead of bind_var.

try_bind accepts any serializable struct while bind_var only allow struct that can be converted into serde_json::Value. Also, try_bind is failable that it returns a Result<_,_>.

Oh I found the doc doesn't contain discription on how to use AqlQueryBuilder, that is something to be improved.

[inzanez]

Yes, I agree, try_bind works exactly as I expected. Many thanks!