fedimint_core/
invite_code.rs

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1use core::fmt;
2use std::borrow::Cow;
3use std::collections::BTreeMap;
4use std::fmt::{Display, Formatter};
5use std::io::Read;
6use std::str::FromStr;
7
8use anyhow::ensure;
9use bech32::{Bech32m, Hrp};
10use serde::{Deserialize, Serialize};
11
12use crate::base32::FEDIMINT_PREFIX;
13use crate::config::FederationId;
14use crate::encoding::{Decodable, DecodeError, Encodable};
15use crate::module::registry::{ModuleDecoderRegistry, ModuleRegistry};
16use crate::util::SafeUrl;
17use crate::{NumPeersExt, PeerId};
18
19/// Information required for client to join Federation
20///
21/// Can be used to download the configs and bootstrap a client.
22///
23/// ## Invariants
24/// Constructors have to guarantee that:
25///   * At least one Api entry is present
26///   * At least one Federation ID is present
27#[derive(Clone, Debug, Eq, PartialEq, Encodable, Hash, Ord, PartialOrd)]
28pub struct InviteCode(Vec<InviteCodePart>);
29
30impl Decodable for InviteCode {
31    fn consensus_decode_partial<R: Read>(
32        r: &mut R,
33        modules: &ModuleDecoderRegistry,
34    ) -> Result<Self, DecodeError> {
35        let inner: Vec<InviteCodePart> = Decodable::consensus_decode_partial(r, modules)?;
36
37        if !inner
38            .iter()
39            .any(|data| matches!(data, InviteCodePart::Api { .. }))
40        {
41            return Err(DecodeError::from_str(
42                "No API was provided in the invite code",
43            ));
44        }
45
46        if !inner
47            .iter()
48            .any(|data| matches!(data, InviteCodePart::FederationId(_)))
49        {
50            return Err(DecodeError::from_str(
51                "No Federation ID provided in invite code",
52            ));
53        }
54
55        Ok(Self(inner))
56    }
57}
58
59impl InviteCode {
60    pub fn new(
61        url: SafeUrl,
62        peer: PeerId,
63        federation_id: FederationId,
64        api_secret: Option<String>,
65    ) -> Self {
66        let mut s = Self(vec![
67            InviteCodePart::Api { url, peer },
68            InviteCodePart::FederationId(federation_id),
69        ]);
70
71        if let Some(api_secret) = api_secret {
72            s.0.push(InviteCodePart::ApiSecret(api_secret));
73        }
74
75        s
76    }
77
78    pub fn from_map(
79        peer_to_url_map: &BTreeMap<PeerId, SafeUrl>,
80        federation_id: FederationId,
81        api_secret: Option<String>,
82    ) -> Self {
83        let max_size = peer_to_url_map.to_num_peers().max_evil() + 1;
84        let mut code_vec: Vec<InviteCodePart> = peer_to_url_map
85            .iter()
86            .take(max_size)
87            .map(|(peer, url)| InviteCodePart::Api {
88                url: url.clone(),
89                peer: *peer,
90            })
91            .collect();
92
93        code_vec.push(InviteCodePart::FederationId(federation_id));
94
95        if let Some(api_secret) = api_secret {
96            code_vec.push(InviteCodePart::ApiSecret(api_secret));
97        }
98
99        Self(code_vec)
100    }
101
102    /// Constructs an [`InviteCode`] which contains as many guardian URLs as
103    /// needed to always be able to join a working federation
104    pub fn new_with_essential_num_guardians(
105        peer_to_url_map: &BTreeMap<PeerId, SafeUrl>,
106        federation_id: FederationId,
107    ) -> Self {
108        let max_size = peer_to_url_map.to_num_peers().max_evil() + 1;
109        let mut code_vec: Vec<InviteCodePart> = peer_to_url_map
110            .iter()
111            .take(max_size)
112            .map(|(peer, url)| InviteCodePart::Api {
113                url: url.clone(),
114                peer: *peer,
115            })
116            .collect();
117        code_vec.push(InviteCodePart::FederationId(federation_id));
118
119        Self(code_vec)
120    }
121
122    /// Returns the API URL of one of the guardians.
123    pub fn url(&self) -> SafeUrl {
124        self.0
125            .iter()
126            .find_map(|data| match data {
127                InviteCodePart::Api { url, .. } => Some(url.clone()),
128                _ => None,
129            })
130            .expect("Ensured by constructor")
131    }
132
133    /// Api secret, if needed, to use when communicating with the federation
134    pub fn api_secret(&self) -> Option<String> {
135        self.0.iter().find_map(|data| match data {
136            InviteCodePart::ApiSecret(api_secret) => Some(api_secret.clone()),
137            _ => None,
138        })
139    }
140    /// Returns the id of the guardian from which we got the API URL, see
141    /// [`InviteCode::url`].
142    pub fn peer(&self) -> PeerId {
143        self.0
144            .iter()
145            .find_map(|data| match data {
146                InviteCodePart::Api { peer, .. } => Some(*peer),
147                _ => None,
148            })
149            .expect("Ensured by constructor")
150    }
151
152    /// Get all peer URLs in the [`InviteCode`]
153    pub fn peers(&self) -> BTreeMap<PeerId, SafeUrl> {
154        self.0
155            .iter()
156            .filter_map(|entry| match entry {
157                InviteCodePart::Api { url, peer } => Some((*peer, url.clone())),
158                _ => None,
159            })
160            .collect()
161    }
162
163    /// Returns the federation's ID that can be used to authenticate the config
164    /// downloaded from the API.
165    pub fn federation_id(&self) -> FederationId {
166        self.0
167            .iter()
168            .find_map(|data| match data {
169                InviteCodePart::FederationId(federation_id) => Some(*federation_id),
170                _ => None,
171            })
172            .expect("Ensured by constructor")
173    }
174}
175
176/// For extendability [`InviteCode`] consists of parts, where client can ignore
177/// ones they don't understand.
178///
179/// ones they don't understand Data that can be encoded in the invite code.
180/// Currently we always just use one `Api` and one `FederationId` variant in an
181/// invite code, but more can be added in the future while still keeping the
182/// invite code readable for older clients, which will just ignore the new
183/// fields.
184#[derive(Clone, Debug, Eq, PartialEq, Encodable, Decodable, Hash, Ord, PartialOrd)]
185enum InviteCodePart {
186    /// API endpoint of one of the guardians
187    Api {
188        /// URL to reach an API that we can download configs from
189        url: SafeUrl,
190        /// Peer id of the host from the Url
191        peer: PeerId,
192    },
193
194    /// Authentication id for the federation
195    FederationId(FederationId),
196
197    /// Api secret to use
198    ApiSecret(String),
199
200    /// Unknown invite code fields to be defined in the future
201    #[encodable_default]
202    Default { variant: u64, bytes: Vec<u8> },
203}
204
205/// We can represent client invite code as a bech32 string for compactness and
206/// error-checking
207///
208/// Human readable part (HRP) includes the version
209/// ```txt
210/// [ hrp (4 bytes) ] [ id (48 bytes) ] ([ url len (2 bytes) ] [ url bytes (url len bytes) ])+
211/// ```
212const BECH32_HRP: Hrp = Hrp::parse_unchecked("fed1");
213
214impl FromStr for InviteCode {
215    type Err = anyhow::Error;
216
217    fn from_str(encoded: &str) -> Result<Self, Self::Err> {
218        if let Ok(invite_code) = crate::base32::decode_prefixed(FEDIMINT_PREFIX, encoded) {
219            return Ok(invite_code);
220        }
221
222        let (hrp, data) = bech32::decode(encoded)?;
223
224        ensure!(hrp == BECH32_HRP, "Invalid HRP in bech32 encoding");
225
226        let invite = Self::consensus_decode_whole(&data, &ModuleRegistry::default())?;
227
228        Ok(invite)
229    }
230}
231
232/// Parses the invite code from a bech32 string
233impl Display for InviteCode {
234    fn fmt(&self, formatter: &mut Formatter<'_>) -> fmt::Result {
235        let data = self.consensus_encode_to_vec();
236        let encode = bech32::encode::<Bech32m>(BECH32_HRP, &data).map_err(|_| fmt::Error)?;
237        formatter.write_str(&encode)
238    }
239}
240
241impl Serialize for InviteCode {
242    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
243    where
244        S: serde::Serializer,
245    {
246        String::serialize(&self.to_string(), serializer)
247    }
248}
249
250impl<'de> Deserialize<'de> for InviteCode {
251    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
252    where
253        D: serde::Deserializer<'de>,
254    {
255        let string = Cow::<str>::deserialize(deserializer)?;
256        Self::from_str(&string).map_err(serde::de::Error::custom)
257    }
258}
259
260#[cfg(test)]
261mod tests {
262    use std::str::FromStr;
263
264    use fedimint_core::PeerId;
265    use fedimint_core::base32::FEDIMINT_PREFIX;
266
267    use crate::config::FederationId;
268    use crate::invite_code::InviteCode;
269
270    #[test]
271    fn test_invite_code_to_from_string() {
272        let invite_code_str = "fed11qgqpu8rhwden5te0vejkg6tdd9h8gepwd4cxcumxv4jzuen0duhsqqfqh6nl7sgk72caxfx8khtfnn8y436q3nhyrkev3qp8ugdhdllnh86qmp42pm";
273        let invite_code = InviteCode::from_str(invite_code_str).expect("valid invite code");
274
275        InviteCode::from_str(&crate::base32::encode_prefixed(
276            FEDIMINT_PREFIX,
277            &invite_code,
278        ))
279        .expect("Failed to parse base 32 invite code");
280
281        assert_eq!(invite_code.to_string(), invite_code_str);
282        assert_eq!(
283            invite_code.0,
284            [
285                crate::invite_code::InviteCodePart::Api {
286                    url: "wss://fedimintd.mplsfed.foo/".parse().expect("valid url"),
287                    peer: PeerId::new(0),
288                },
289                crate::invite_code::InviteCodePart::FederationId(FederationId(
290                    bitcoin::hashes::sha256::Hash::from_str(
291                        "bea7ff4116f2b1d324c7b5d699cce4ac7408cee41db2c88027e21b76fff3b9f4"
292                    )
293                    .expect("valid hash")
294                ))
295            ]
296        );
297    }
298}
fedimint_core/invite_code.rs

fedimint_core/
invite_code.rs
