feat(corp/rih): implement backend captcha validation r/6264

Change-Id: Ia80a6aeb8c20bdacbf93356be31592ca4ba7fcdc
Reviewed-on: https://cl.tvl.fyi/c/depot/+/8741
Autosubmit: tazjin <tazjin@tvl.su>
Reviewed-by: tazjin <tazjin@tvl.su>
Tested-by: BuildkiteCI

3 files changed, 42 insertions, 0 deletions

diff --git a/corp/rih/backend/Cargo.lock b/corp/rih/backend/Cargo.lock
index 8e6465fe357c..afbe6fbc0bf4 100644
--- a/corp/rih/backend/Cargo.lock
+++ b/corp/rih/backend/Cargo.lock
@@ -671,6 +671,7 @@ name = "rih-backend"
 version = "0.1.0"
 dependencies = [
  "anyhow",
+ "attohttpc",
  "log",
  "rouille",
  "rust-s3",
diff --git a/corp/rih/backend/Cargo.toml b/corp/rih/backend/Cargo.toml
index 16d7d4d48416..97d4821e3bf7 100644
--- a/corp/rih/backend/Cargo.toml
+++ b/corp/rih/backend/Cargo.toml
@@ -10,6 +10,11 @@ serde = { version = "1.0", features = [ "derive" ] }
 serde_json = "1.0"
 uuid = { version = "1.3.3", features = ["v4", "serde"] }
 
+[dependencies.attohttpc]
+version = "0.22"
+default-features = false
+features = [ "tls-rustls" ]
+
 [dependencies.rouille]
 version = "3.6"
 default-features = false
diff --git a/corp/rih/backend/src/main.rs b/corp/rih/backend/src/main.rs
index c696858da5a4..208e0367c6a8 100644
--- a/corp/rih/backend/src/main.rs
+++ b/corp/rih/backend/src/main.rs
@@ -43,6 +43,40 @@ impl Record {
     }
 }
 
+fn validate_captcha(token: &str) -> Result<()> {
+    // TODO(tazjin): pass `ip` parameter
+    let url = "https://smartcaptcha.yandexcloud.net/validate";
+    let backend_key =
+        env::var("YANDEX_SMARTCAPTCHA_KEY").context("captcha verification key not provided")?;
+
+    #[derive(Deserialize)]
+    struct CaptchaResponse {
+        status: String,
+        message: String,
+    }
+
+    let response: CaptchaResponse = attohttpc::get(url)
+        .param("secret", backend_key)
+        .param("token", token)
+        .send()
+        .context("failed to send captcha verification request")?
+        .error_for_status()
+        .context("captcha verification request failed")?
+        .json()
+        .context("failed to deserialize captcha verification response")?;
+
+    if response.status != "ok" {
+        warn!(
+            "invalid captcha: {} ({})",
+            response.message, response.status
+        );
+    }
+
+    info!("captcha token was valid");
+
+    Ok(())
+}
+
 fn persist_record(ip: &SocketAddr, record: &Record) -> Result<()> {
     let bucket_name = "rih-backend-data";
     let credentials =
@@ -88,6 +122,8 @@ fn handle_submit(req: &Request) -> Result<Response> {
     let submitted: FrontendReq =
         rouille::input::json::json_input(req).context("failed to deserialise frontend request")?;
 
+    validate_captcha(&submitted.captcha_token)?;
+
     if !submitted.record.validate() {
         bail!("invalid record: {:?}", submitted.record);
     }