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OAuth Requests, APIs, Diesel, and Sessions

jculverhouse profile image Jeff Culverhouse Originally published at rust.graystorm.com on ・8 min read

Designing a Full-Featured WebApp with Rust (6 Part Series)

1) Piecing Together a Rust Web Application 2) Adding Rocket to my Rust Web Application 3 ... 4 3) It’s Not a Web Application Without a Database 4) Better Logging for the Web Application 5) Rust Web App Session Management with AWS 6) OAuth Requests, APIs, Diesel, and Sessions

Intertwined woven basket material.. much like Oauth, accounts, APIs, diesel, and sessions are in this project (probably any project)

Things are starting to intertwine…

Some big changes in the repository just recently. I added Google Signin and Facebook Signin OAuth connections. I’m thinking I may not even configure an internal password on the site for users and instead just require one of those options. Probably I’ll add more, like 500px.com and/or Flickr, given the site’s purpose. A password field is still in my database though, so I haven’t given up the idea completely. Also, the OAuth requests create accounts using Diesel.

Users (now identified as shooters – we photographers haven’t given up that term) – are now written to the db. I really fought with one Diesel feature, so that bit is still commented out in the code. In addition, I added my first API to POST to – so another step with the Rocketcrate as well! I’d like to work my way into playing with a GraphQL endpoint so I can play with that as well!! (What’s the limit on Crate dependencies in a project anyway?!) I’m starting to think I won’t be able to tackle all of this in a single post – but let start!

OAuth vs Old and New Accounts

When a user arrives on the site, I check for a cookie with a session id (see my previous post). I decided, for now, I would use the User Agent (plus some random characters) as a fingerprint for creating the session id. So, when I am able to get a session_id from a cookie, I want to verify the User Agent is the same and that the session hasn’t expired. If the user arrives brand new, without a cookie, I immediately create an empty, no-user session for them. All of this is done, for now, right at the top of my index() route.

<src/routes.rs>

...
#[get("/")]
pub fn index(mut cookies: Cookies, nginx: Nginx) -> 
    rocket_contrib::templates::Template
{
    let session = get_or_setup_session(&mut cookies, &nginx);
...

After the index page loads, it shows the Google and Facebook Sign In buttons. Clicking one of those, they do the validation dance and get permission from the user. When that is granted, my app gets a token back which I send up to the server via a POST to /api/v1/tokensignin.

<src/api.rs>

use rocket::{http::Cookies, post, request::Form, FromForm};
use crate::oauth::*;
use crate::routes::Nginx;
use crate::session::*;
#[derive(FromForm)]
pub struct OAuthReq {
    pub g_token: Option<String>,  // google login req
    pub fb_token: Option<String>, // facebook login req`
    pub name: String,
    pub email: String,
}
#[post("/api/v1/tokensignin", data = "<oauth_req>")]
pub fn tokensignin(mut cookies: Cookies, nginx: Nginx,
        oauth_req: Form<OAuthReq>) -> String
{
    let mut session = get_or_setup_session(&mut cookies, &nginx);
    if let Some(token) = &oauth_req.g_token {
        match verify_google_oauth(&mut session, &token,
            &oauth_req.name, &oauth_req.email)
        {
            true => {
                session.google_oauth = true;
                save_session_to_ddb(&mut session);
                "success".to_string()
            }
            false => {
                session.google_oauth = false;
                save_session_to_ddb(&mut session);
                "failed".to_string()
            }
        }
    } else if let Some(token) = &oauth_req.fb_token {
        match verify_facebook_oauth(&mut session, &token,
            &oauth_req.name, &oauth_req.email)
        {
            true => {
                session.facebook_oauth = true;
                save_session_to_ddb(&mut session);
                "success".to_string()
            }
            false => {
                session.facebook_oauth = false;
                save_session_to_ddb(&mut session);
                "failed".to_string()
            }
        }
    } else {
        "no token sent".to_string()
    }
}

OAuth Requests via HTTP POSTs

This is how you allow for a POST and form data to come in – you setup a struct (OAuthReq in my example) of what you expect and bring that in as an input param. Plus, I am also bringing in any cookies that arrive with the request plus some Nginx headers so I have access to UserAgent. In the code so far, I’m either verifying a Google or Facebook token. Let’s look at the Google example (the Facebook one is nearly the same). Here are the relevant parts, but I’ll break some pieces down and go through it:

<src/oauth.rs>

...
pub fn verify_google_oauth(
    session: &mut Session,
    token: &String,
    name: &String,
    email: &String,
) -> bool {
    let mut google = google_signin::Client::new();
    google.audiences.push(CONFIG.google_api_client_id.clone());
    let id_info = google.verify(&token).expect("Expected token to be valid");
    let token = id_info.sub.clone();
    verify_token(session, "google".to_string(), &token, &name, &email)
}

Which leads right away to a big match:

fn verify_token(
    session: &mut Session,
    vendor: String,
    token: &String,
    name: &String,
    email: &String,
) -> bool {
    use crate::schema::oauth::dsl::*;
    use crate::schema::shooter::dsl::*;
    let connection = connect_pgsql();
    match oauth
        .filter(oauth_vendor.eq(&vendor))
        .filter(oauth_user.eq(&token))
        .first::<Oauth>(&connection)
    {

With the OK arm:

        // token WAS found in oauth table
        Ok(o) => {
            if let Some(id) = session.shooter_id {
                if id == o.shooter_id {
                    return true;
                } else {
                    return false;
                }
            } else {
                // log in user - what IS the problem with BelongsTo!?
                //if let Ok(s) = Shooter::belonging_to(&o)
                //    .load::<Shooter>(&connection)
                //{
                //    session.shooter_id = Some(shooter.shooter_id);
                //    session.shooter_name = Some(shooter.shooter_name);
                //    session.email_address = Some(shooter.email);
                return true;
                //} else {
                //    return false;
                //}
            }
        }

And the ERR arms:

        // token not found in oauth table
        Err(diesel::NotFound) => match session.shooter_id {
            Some(id) => {
                create_oauth(&connection, &vendor, token, id);
                true
            }
            None => match shooter
                .filter(shooter_email.eq(&email))
                .first::<Shooter>(&connection)
            {
                // email address WAS found in shooter table
                Ok(s) => {
                    create_oauth(&connection, &vendor, token, s.shooter_id);
                    true
                }
                // email address not found in shooter table
                Err(diesel::NotFound) => {
                    let this_shooter =
                        create_shooter(&connection, name, None,
                            email, &"active".to_string());
                    session.shooter_id = Some(this_shooter.shooter_id);
                    create_oauth(&connection, &vendor, token,
                        this_shooter.shooter_id);
                    true
                }
                Err(e) => {
                    panic!("Database error {}", e);
                }
            },
        },
        Err(e) => {
            panic!("Database error {}", e);
        }
    }
}

Simple Queries with Diesel

Breaking all that code down to smaller bits: first, I query the PgSQL database for the given oauth user:

match oauth
    .filter(oauth_vendor.eq(&vendor))
    .filter(oauth_user.eq(&token))
    .first::<Oauth>(&connection) {
        Ok(o) => { ... }
        Err(diesel::NotFound) => { ... }
        Err(e) => { ... }
}

Check the oauth table for records WHERE (filter) the oauth_vendor is (google or facebook) AND I’ve already stored the same validated oauth_user. I will get back either Ok(o) or Err(diesel::NotFound) … (or some worse error message), so I make a pattern with those 3 arms.

If we did get a hit from the DB, that session id is already tied to a shooter_id (user id) unless something is very wrong. So, IF we also have a shooter_id defined in our current session, I just need to verify that they match and return true or false. But, if we don’t have a shooter_id in our session, we know the oauth is tied to a shooter in the db, so this will log them in. Diesel has an easy way to get that parent record, which is what this should do:

// if let Ok(s) = Shooter::belonging\_to(&o).load::\<Shooter\>(&connection) {
...

I fought and fought to get this work, but you can see it is still commented out. From posts and chat around the Internet, I believe it can work – I think I either have a scope problem or my models aren’t setup correctly… this is how they look:

<src/model.rs>

...
#[derive(Identifiable, Queryable, Debug, PartialEq)]
#[table_name = "shooter"]
#[primary_key("shooter_id")]
pub struct Shooter {
    pub shooter_id: i32,
    pub shooter_name: String,
    pub shooter_password: String,
    pub shooter_status: String,
    pub shooter_email: String,
    pub shooter_real_name: String,
    pub shooter_create_time: chrono::NaiveDateTime,
    pub shooter_active_time: Option<chrono::NaiveDateTime>,
    pub shooter_inactive_time: Option<chrono::NaiveDateTime>,
    pub shooter_remove_time: Option<chrono::NaiveDateTime>,
    pub shooter_modify_time: chrono::NaiveDateTime,
}
...
#[derive(Identifiable, Associations, Queryable, Debug, PartialEq)]
#[belongs_to(Shooter, foreign_key = "shooter_id")]
#[table_name = "oauth"]
#[primary_key("oauth_id")]
pub struct Oauth {
    pub oauth_id: i32,
    pub oauth_vendor: String,
    pub oauth_user: String,
    pub shooter_id: i32,
    pub oauth_status: String,
    pub oauth_create_time: chrono::NaiveDateTime,
    pub oauth_last_use_time: chrono::NaiveDateTime,
    pub oauth_modify_time: chrono::NaiveDateTime,
}

I’ll get it to work eventually – I really hope it isn’t failing because I didn’t specifically name my primary fields just id like in the examples Diesel gives in their guides. It seems like naming shooter_id in table oauth to match shooter_id in the shooter table should make things obvious. Hopefully we aren’t forced to always use id as the primary field… no, that can’t be it.

Anyway, back to verifying. The other main case is that an oauth record with this token is NOT found in the table. Which means it is a new connection we haven’t seen before. If the session is already logged in, we just need to attach this oauth token to the logged in user and return true!

Some(id) => {
    create_oauth(&connection, &vendor, token, id);
    true
}

Otherwise, two choices – we will try to match on an existing shooter via the email address. If we find a match, we log them in and again attach this oauth token to their shooter record.

 None => match shooter
     .filter(shooter_email.eq(&email))
     .first::<Shooter>(&connection)
 {
     // email address WAS found in shooter table
     Ok(s) => {
         create_oauth(&connection, &vendor, token, s.shooter_id);
         true
     }

Otherwise, we don’t get a hit; that is, we haven’t seen this oauth token before AND we haven’t seen this validated email address before. We have to call that a brand new shooter account. I mentioned we create accounts from the OAuth requests using Diesel – this is where that happens. In this case, we create both the shooter record and the oauth record, linking them together.

// email address not found in shooter table
Err(diesel::NotFound) => {
    let this_shooter =
        create_shooter(&connection, name, None, email,
            &"active".to_string());
    session.shooter_id = Some(this_shooter.shooter_id);
    create_oauth(&connection, &vendor, token, this_shooter.shooter_id);
    true
}

Using Diesel to Insert Records

As we fall back out of the stack of functions we’ve called, because we return true here the session will get updated with the shooter_id – they are now logged in. Also, the shooter and oauth records are saved, so if they come back, they can just validate and be logged into their same account again. Here are the two methods that create those records:

<src/shooter.rs>

...
pub fn create_shooter<'a>(
    connection: &PgConnection,
    name: &'a String,
    password: Option<&'a String>,
    email: &'a String,
    status: &'a String,
) -> Shooter {
    use crate::schema::shooter::dsl::*;
    let new_shooter = NewShooter {
        shooter_name: name.to_string(),
        shooter_password: match password {
            Some(p) => p.to_string(),
            None => thread_rng()
                .sample_iter(&Alphanumeric)
                .take(64)
                .collect::<String>(),
        },
        shooter_status: status.to_string(),
        shooter_email: email.to_string(),
        shooter_real_name: name.to_string(),
    };
    diesel::insert_into(shooter)
        .values(&new_shooter)
        .get_result(connection)
        .expect("Error saving new Shooter")
}
<src/oauth.rs>

...
pub fn create_oauth<'a>(
    connection: &PgConnection,
    vendor: &'a String,
    user_id: &'a String,
    shooterid: i32,
) -> Oauth {
    use crate::schema::oauth::dsl::*;
    let new_oauth = NewOauth {
        oauth_vendor: vendor.to_string(),
        oauth_user: user_id.to_string(),
        shooter_id: shooterid,
    };
    diesel::insert_into(oauth)
        .values(&new_oauth)
        .get_result(connection)
        .expect("Error saving new Oauth")
}

As far as writing these new records to PgSQL – in both cases, we have NewShooter and NewOauth structs that allow us to set the bare minimum of fields without having to worry about the fields that PgSQL will default for us (like the create_date fields). We setup the appropriate struct and pass it to insert_into(). Adding .get_result() will return the newly created record to us, so we have access to the brand new shooter_id or oauth_id.

Complexity

If a user comes to the site, signs in with one OAuth (which creates their shooter record and attaches that oauth token) and then signs in with the other, this logic figures out they are validated to be the same person, so creates just a single shooter record with two oauth records, and both point to the one user. If they come back, they can authenticate via either third-party and are allowed back in.

Ok, more to come as I figure out other problems. I haven’t gone through that logic tightly enough to make sure I don’t have any holes – and it wouldn’t surprise me to find some. It doesn’t really matter – this is certainly teaching me Rust! Give it a try at PinpointShooting.com – but don’t be surprised if you shooter account gets deleted, constantly.

The post OAuth Requests, APIs, Diesel, and Sessions appeared first on Learning Rust.

Designing a Full-Featured WebApp with Rust (6 Part Series)

1) Piecing Together a Rust Web Application 2) Adding Rocket to my Rust Web Application 3 ... 4 3) It’s Not a Web Application Without a Database 4) Better Logging for the Web Application 5) Rust Web App Session Management with AWS 6) OAuth Requests, APIs, Diesel, and Sessions

Posted on Aug 8 '19 by:

jculverhouse profile

Jeff Culverhouse

@jculverhouse

I am a remote Sr Software Engineer for ZipRecruiter.com, mainly perl, but learning Rust in my spare time. Plus taking classes at James Madison University.

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