refactor: add attestation middleware

Signed-off-by: Gustavo Inacio <[email protected]>

Author: gusinacio

crates/service/src/middleware.rs

@@ -1,6 +1,7 @@
 // Copyright 2023-, Edge & Node, GraphOps, and Semiotic Labs.
 // SPDX-License-Identifier: Apache-2.0
 
+mod attestation;
 pub mod auth;
 mod inject_allocation;
 mod inject_attestation_signer;

crates/service/src/middleware/attestation.rs

@@ -0,0 +1,95 @@
+// Copyright 2023-, Edge & Node, GraphOps, and Semiotic Labs.
+// SPDX-License-Identifier: Apache-2.0
+
+use std::string::FromUtf8Error;
+
+use axum::{
+    body::to_bytes,
+    extract::Request,
+    middleware::Next,
+    response::{IntoResponse, Response},
+};
+use reqwest::StatusCode;
+use serde::Serialize;
+use thegraph_core::Attestation;
+
+use indexer_attestation::AttestationSigner;
+
+#[derive(Clone)]
+pub enum AttestationInput {
+    Attestable { req: String },
+    NotAttestable,
+}
+
+#[derive(Debug, Serialize)]
+pub struct IndexerResponsePayload {
+    #[serde(rename = "graphQLResponse")]
+    graphql_response: String,
+    attestation: Option<Attestation>,
+}
+
+/// check if the query can be attestable generates attestation
+/// executes query -> return subgraph response: (string, attestable (bool))
+/// if attestable && allocation id:
+///     - look for signer
+///     - create attestation
+///     - return response with attestation
+/// else:
+///     - return with no attestation
+///
+/// Required AttestationSigner
+pub async fn attestation_middleware(
+    request: Request,
+    next: Next,
+) -> Result<Response, AttestationError> {
+    let signer = request
+        .extensions()
+        .get::<AttestationSigner>()
+        .cloned()
+        .ok_or(AttestationError::CouldNotFindSigner)?;
+
+    let (parts, graphql_response) = next.run(request).await.into_parts();
+    let attestation_response = parts.extensions.get::<AttestationInput>();
+    let bytes = to_bytes(graphql_response, usize::MAX).await?;
+    let res = String::from_utf8(bytes.into())?;
+
+    let attestation = match attestation_response {
+        Some(AttestationInput::Attestable { req }) => Some(signer.create_attestation(req, &res)),
+        _ => None,
+    };
+
+    Ok(Response::new(
+        serde_json::to_string(&IndexerResponsePayload {
+            graphql_response: res,
+            attestation,
+        })?
+        .into(),
+    ))
+}
+
+#[derive(thiserror::Error, Debug)]
+pub enum AttestationError {
+    #[error("Could not find signer for allocation")]
+    CouldNotFindSigner,
+
+    #[error("There was an AxumError: {0}")]
+    AxumError(#[from] axum::Error),
+
+    #[error("There was an error converting the response to UTF-8 string: {0}")]
+    FromUtf8Error(#[from] FromUtf8Error),
+
+    #[error("there was an error while serializing the response: {0}")]
+    SerializationError(#[from] serde_json::Error),
+}
+
+impl IntoResponse for AttestationError {
+    fn into_response(self) -> Response {
+        match self {
+            AttestationError::CouldNotFindSigner
+            | AttestationError::AxumError(_)
+            | AttestationError::FromUtf8Error(_)
+            | AttestationError::SerializationError(_) => StatusCode::INTERNAL_SERVER_ERROR,
+        }
+        .into_response()
+    }
+}