1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167

use {
    crate::{AwsSigV4VerifierService, ErrorMapper},
    derive_builder::Builder,
    http::method::Method,
    hyper::{body::Body, server::conn::AddrStream, service::Service, Request, Response},
    scratchstack_aws_signature::{
        GetSigningKeyRequest, GetSigningKeyResponse, SignatureOptions, SignedHeaderRequirements,
    },
    std::{
        future::Future,
        pin::Pin,
        task::{Context, Poll},
    },
    tokio::net::TcpStream,
    tokio_rustls::server::TlsStream,
    tower::BoxError,
};

/// A Hyper service spawner that wraps a SigV4 signing key provider ([`GetSigningKeyRequest`] ->
/// [`GetSigningKeyResponse`]), an HTTP request handler ([`Request<Body>`] -> [`Response<Body>`]) for handling
/// requests that pass authentication, and an error mapper ([`ErrorMapper`]) for converting authentication errors into
/// HTTP responses.
#[derive(Builder, Clone, Debug)]
pub struct SpawnService<G, S, E>
where
    G: Service<GetSigningKeyRequest, Response = GetSigningKeyResponse, Error = BoxError> + Clone + Send + 'static,
    G::Future: Send,
    S: Service<Request<Body>, Response = Response<Body>, Error = BoxError> + Clone + Send + 'static,
    S::Future: Send,
    E: ErrorMapper,
{
    /// The region this service is operating in.
    #[builder(setter(into))]
    region: String,

    /// The name of this service.
    #[builder(setter(into))]
    service: String,

    /// The allowed HTTP request methods.
    #[builder(default)]
    allowed_request_methods: Vec<Method>,

    /// The allowed HTTP content types.
    #[builder(default)]
    allowed_content_types: Vec<String>,

    /// The HTTP headers that must be signed in the SigV4 signature.
    #[builder(default)]
    signed_header_requirements: SignedHeaderRequirements,

    /// The signing key provider.
    get_signing_key: G,

    /// The service implementation.
    implementation: S,

    /// The mapper for converting authentication errors into HTTP responses.
    error_mapper: E,

    /// Options for the signature verification process.
    #[builder(default)]
    signature_options: SignatureOptions,
}

impl<G, S, E> SpawnService<G, S, E>
where
    G: Service<GetSigningKeyRequest, Response = GetSigningKeyResponse, Error = BoxError> + Clone + Send + 'static,
    G::Future: Send,
    S: Service<Request<Body>, Response = Response<Body>, Error = BoxError> + Clone + Send + 'static,
    S::Future: Send,
    E: ErrorMapper,
{
    /// Create a new [SpawnServiceBuilder] for constructing a [SpawnService].
    #[inline]
    pub fn builder() -> SpawnServiceBuilder<G, S, E> {
        SpawnServiceBuilder::default()
    }
}

impl<G, S, E> Service<&AddrStream> for SpawnService<G, S, E>
where
    G: Service<GetSigningKeyRequest, Response = GetSigningKeyResponse, Error = BoxError> + Clone + Send + 'static,
    G::Future: Send,
    S: Service<Request<Body>, Response = Response<Body>, Error = BoxError> + Clone + Send + 'static,
    S::Future: Send,
    E: ErrorMapper,
{
    type Response = AwsSigV4VerifierService<G, S, E>;
    type Error = BoxError;
    type Future = Pin<Box<dyn Future<Output = Result<Self::Response, Self::Error>> + Send>>;

    fn poll_ready(&mut self, _cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
        Poll::Ready(Ok(()))
    }

    fn call(&mut self, _req: &AddrStream) -> Self::Future {
        let region = self.region.clone();
        let service = self.service.clone();
        let allowed_request_methods = self.allowed_request_methods.clone();
        let allowed_content_types = self.allowed_content_types.clone();
        let signed_header_requirements = self.signed_header_requirements.clone();
        let get_signing_key = self.get_signing_key.clone();
        let implementation = self.implementation.clone();
        let error_mapper = self.error_mapper.clone();
        let signature_options = self.signature_options;

        Box::pin(async move {
            AwsSigV4VerifierService::builder()
                .region(region)
                .service(service)
                .allowed_request_methods(allowed_request_methods)
                .allowed_content_types(allowed_content_types)
                .signed_header_requirements(signed_header_requirements)
                .get_signing_key(get_signing_key)
                .implementation(implementation)
                .error_mapper(error_mapper)
                .signature_options(signature_options)
                .build()
                .map_err(Into::into)
        })
    }
}

impl<G, S, E> Service<&TlsStream<TcpStream>> for SpawnService<G, S, E>
where
    G: Service<GetSigningKeyRequest, Response = GetSigningKeyResponse, Error = BoxError> + Clone + Send + 'static,
    G::Future: Send,
    S: Service<Request<Body>, Response = Response<Body>, Error = BoxError> + Clone + Send + 'static,
    S::Future: Send,
    E: ErrorMapper,
{
    type Response = AwsSigV4VerifierService<G, S, E>;
    type Error = BoxError;
    type Future = Pin<Box<dyn Future<Output = Result<Self::Response, Self::Error>> + Send>>;

    fn poll_ready(&mut self, _cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
        Poll::Ready(Ok(()))
    }

    fn call(&mut self, _req: &TlsStream<TcpStream>) -> Self::Future {
        let region = self.region.clone();
        let service = self.service.clone();
        let allowed_request_methods = self.allowed_request_methods.clone();
        let allowed_content_types = self.allowed_content_types.clone();
        let signed_header_requirements = self.signed_header_requirements.clone();
        let get_signing_key = self.get_signing_key.clone();
        let implementation = self.implementation.clone();
        let error_mapper = self.error_mapper.clone();
        let signature_options = self.signature_options;

        Box::pin(async move {
            AwsSigV4VerifierService::builder()
                .region(region)
                .service(service)
                .allowed_request_methods(allowed_request_methods)
                .allowed_content_types(allowed_content_types)
                .signed_header_requirements(signed_header_requirements)
                .get_signing_key(get_signing_key)
                .implementation(implementation)
                .error_mapper(error_mapper)
                .signature_options(signature_options)
                .build()
                .map_err(Into::into)
        })
    }
}