stash

frontend/src/federation.js

@@ -0,0 +1,107 @@
+class ServerSet {
+    constructor(servers, unreachable_neighbors) {
+        if (!servers || !Array.isArray(servers)) {
+            throw new Error('no servers')
+        }
+        if (!unreachable_neighbors || typeof unreachable_neighbors.queryUnreachable !== 'function' || typeof unreachable_neighbors.unreachable !== 'function') {
+            throw new Error('no unreachable_neighbors')
+        }
+        this.servers = servers;
+        this.unreachable_neighbors = unreachable_neighbors;
+    }
+
+    add(server) {
+        this.servers.push(server);
+    }
+
+    async post(auth, target, data) {
+        if (!auth || typeof auth.buildAuthHeader !== 'function') {
+            throw new Error('no auth')
+        }
+        for (const server of this.servers) {
+            try {
+                if (this.unreachable_neighbors.queryUnreachable(server)) {
+                    continue
+                }
+                const url = "http://" + server + target // TODO https
+                return await fetch(url, {
+                    method: 'POST',
+                    headers: {
+                        'Content-Type': 'application/json',
+                        ...auth.buildAuthHeader(url)
+                    },
+                    credentials: 'omit',
+                    body: JSON.stringify(data)
+                }).catch(err => this.unreachable_neighbors.unreachable(server)
+                ).then(response => response.json())
+            } catch (e) {
+                console.error('post to server failed', server, e)
+            }
+        }
+        throw new Error('all servers failed')
+    }
+
+    async get(auth, target) {
+        if (!auth || typeof auth.buildAuthHeader !== 'function') {
+            throw new Error('no auth')
+        }
+        for (const server of this.servers) {
+            try {
+                if (this.unreachable_neighbors.queryUnreachable(server)) {
+                    continue
+                }
+                const url = "http://" + server + target // TODO https
+                return await fetch(url, {
+                    method: 'GET',
+                    headers: {
+                        ...auth.buildAuthHeader(url)
+                    },
+                    credentials: 'omit'
+                }).catch(err => this.unreachable_neighbors.unreachable(server)
+                ).then(response => response.json())
+            } catch (e) {
+                console.error('get from server failed', server, e)
+            }
+        }
+        throw new Error('all servers failed')
+    }
+}
+
+class authMethod {
+    constructor(method, auth) {
+        this.method = method;
+        this.auth = auth;
+    }
+
+    buildAuthHeader(url, data) {
+        return this.method(this.auth, {url, data})
+    }
+
+}
+
+function createSignAuth(username, signKey) {
+    const context = {username, signKey}
+    if (!context.signKey || !context.username || typeof context.username !== 'string'
+        || !(context.signKey instanceof Uint8Array) || context.signKey.length !== 64) {
+        throw new Error('no signKey or username')
+    }
+    return new authMethod(({signKey, username}, {url, data}) => {
+        const json = JSON.stringify(data)
+        const signature = nacl.crypto_sign_detached(nacl.encode_utf8(url + (data ? json : "")), signKey)
+        return {'Authorization': 'Signature ' + username + ':' + nacl.to_hex(signature)}
+    }, context)
+}
+
+function createTokenAuth(token) {
+    const context = {token}
+    if (!context.token) {
+        throw new Error('no token')
+    }
+    return new authMethod(({token}, {url, data}) => {
+        return {'Authorization': 'Token ' + token}
+    }, context)
+}
+
+export {ServerSet, createSignAuth, createTokenAuth}
+
+