From e7286b86bc611faa961d02b0f9047d6eefb9b3a1 Mon Sep 17 00:00:00 2001
From: Monadic Cat <greenmonadcat@gmail.com>
Date: Mon, 24 Jul 2023 22:45:01 -0500
Subject: [PATCH] add extract_interaction()

---
 twilight-util/Cargo.toml                  |  3 ++-
 twilight-util/src/signature_validation.rs | 26 +++++++++++++++++++++++
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/twilight-util/Cargo.toml b/twilight-util/Cargo.toml
index 8fa39da1417..24a92dc58cb 100644
--- a/twilight-util/Cargo.toml
+++ b/twilight-util/Cargo.toml
@@ -15,6 +15,7 @@ version = "0.15.2"
 [dependencies]
 twilight-model = { default-features = false, optional = true, path = "../twilight-model", version = "0.15.2" }
 twilight-validate = { default-features = false, optional = true, path = "../twilight-validate", version = "0.15.1" }
+serde_json = { default-features = false, optional = true, version = "1.0.96" }
 
 # Signature validation
 ed25519-dalek = { version = "2.0.0-rc.2", optional = true, default-features = false}
@@ -30,7 +31,7 @@ builder = ["dep:twilight-model", "dep:twilight-validate"]
 link = ["dep:twilight-model"]
 permission-calculator = ["dep:twilight-model"]
 snowflake = ["dep:twilight-model"]
-signature-validation = ["dep:ed25519-dalek", "dep:hex"]
+signature-validation = ["dep:ed25519-dalek", "dep:hex", "dep:serde_json"]
 full = ["builder", "link", "permission-calculator", "snowflake", "signature-validation"]
 
 [package.metadata.docs.rs]
diff --git a/twilight-util/src/signature_validation.rs b/twilight-util/src/signature_validation.rs
index 335125f876e..97c71a0697c 100644
--- a/twilight-util/src/signature_validation.rs
+++ b/twilight-util/src/signature_validation.rs
@@ -2,6 +2,7 @@
 //! an HTTPS endpoint to send Interactions to.
 
 use ed25519_dalek::{Signature, SignatureError, VerifyingKey};
+use twilight_model::application::interaction::Interaction;
 
 #[derive(Debug)]
 pub struct FromHexError(hex::FromHexError);
@@ -66,3 +67,28 @@ pub fn check_signature(
         Err(e) => Err(SignatureValidationFailure::InvalidSignature(SigError(e))),
     }
 }
+
+pub enum ExtractFailure {
+    Signature(SignatureValidationFailure),
+    Deserialize(serde_json::Error),
+}
+impl From<SignatureValidationFailure> for ExtractFailure {
+    fn from(value: SignatureValidationFailure) -> Self {
+        Self::Signature(value)
+    }
+}
+impl From<serde_json::Error> for ExtractFailure {
+    fn from(value: serde_json::Error) -> Self {
+        Self::Deserialize(value)
+    }
+}
+
+pub fn extract_interaction(
+    sig: &[u8],
+    timestamp: &[u8],
+    body: &[u8],
+    key: &Key,
+) -> Result<Interaction, ExtractFailure> {
+    check_signature(sig, timestamp, body, key)?;
+    Ok(serde_json::from_slice(body)?)
+}