@bsv/sdk
Version:
BSV Blockchain Software Development Kit
482 lines • 23.5 kB
JavaScript
// @ts-nocheck
import * as Utils from '../../primitives/utils.js';
import Random from '../../primitives/Random.js';
import P2PKH from '../../script/templates/P2PKH.js';
import PublicKey from '../../primitives/PublicKey.js';
import { createNonce } from '../utils/createNonce.js';
import { Peer } from '../Peer.js';
import { SimplifiedFetchTransport } from '../transports/SimplifiedFetchTransport.js';
import { SessionManager } from '../SessionManager.js';
import { getVerifiableCertificates } from '../utils/index.js';
const PAYMENT_VERSION = '1.0';
/**
* AuthFetch provides a lightweight fetch client for interacting with servers
* over a simplified HTTP transport mechanism. It integrates session management, peer communication,
* and certificate handling to enable secure and mutually-authenticated requests.
*
* Additionally, it automatically handles 402 Payment Required responses by creating
* and sending BSV payment transactions when necessary.
*/
export class AuthFetch {
sessionManager;
wallet;
callbacks = {};
certificatesReceived = [];
requestedCertificates;
originator;
peers = {};
/**
* Constructs a new AuthFetch instance.
* @param wallet - The wallet instance for signing and authentication.
* @param requestedCertificates - Optional set of certificates to request from peers.
*/
constructor(wallet, requestedCertificates, sessionManager, originator) {
this.wallet = wallet;
this.requestedCertificates = requestedCertificates;
this.sessionManager = sessionManager ?? new SessionManager();
this.originator = originator;
}
/**
* Mutually authenticates and sends a HTTP request to a server.
*
* 1) Attempt the request.
* 2) If 402 Payment Required, automatically create and send payment.
* 3) Return the final response.
*
* @param url - The URL to send the request to.
* @param config - Configuration options for the request, including method, headers, and body.
* @returns A promise that resolves with the server's response, structured as a Response-like object.
*
* @throws Will throw an error if unsupported headers are used or other validation fails.
*/
async fetch(url, config = {}) {
if (typeof config.retryCounter === 'number') {
if (config.retryCounter <= 0) {
throw new Error('Request failed after maximum number of retries.');
}
config.retryCounter--;
}
const response = await new Promise((async (resolve, reject) => {
try {
// Apply defaults
const { method = 'GET', headers = {}, body } = config;
// Extract a base url
const parsedUrl = new URL(url);
const baseURL = parsedUrl.origin;
// Create a new transport for this base url if needed
let peerToUse;
if (typeof this.peers[baseURL] === 'undefined') {
// Create a peer for the request
const newTransport = new SimplifiedFetchTransport(baseURL);
peerToUse = {
peer: new Peer(this.wallet, newTransport, this.requestedCertificates, this.sessionManager, undefined, this.originator),
pendingCertificateRequests: []
};
this.peers[baseURL] = peerToUse;
this.peers[baseURL].peer.listenForCertificatesReceived((senderPublicKey, certs) => {
this.certificatesReceived.push(...certs);
});
this.peers[baseURL].peer.listenForCertificatesRequested((async (verifier, requestedCertificates) => {
try {
this.peers[baseURL].pendingCertificateRequests.push(true);
const certificatesToInclude = await getVerifiableCertificates(this.wallet, requestedCertificates, verifier, this.originator);
await this.peers[baseURL].peer.sendCertificateResponse(verifier, certificatesToInclude);
}
finally {
// Give the backend 500 ms to process the certificates we just sent, before releasing the queue entry
await new Promise(resolve => setTimeout(resolve, 500));
this.peers[baseURL].pendingCertificateRequests.shift();
}
}));
}
else {
// Check if there's a session associated with this baseURL
if (this.peers[baseURL].supportsMutualAuth === false) {
// Use standard fetch if mutual authentication is not supported
try {
const response = await this.handleFetchAndValidate(url, config, this.peers[baseURL]);
resolve(response);
}
catch (error) {
reject(error);
}
return;
}
peerToUse = this.peers[baseURL];
}
// Serialize the simplified fetch request.
const requestNonce = Random(32);
const requestNonceAsBase64 = Utils.toBase64(requestNonce);
const writer = await this.serializeRequest(method, headers, body, parsedUrl, requestNonce);
// Setup general message listener to resolve requests once a response is received
this.callbacks[requestNonceAsBase64] = { resolve, reject };
const listenerId = peerToUse.peer.listenForGeneralMessages((senderPublicKey, payload) => {
// Create a reader
const responseReader = new Utils.Reader(payload);
// Deserialize first 32 bytes of payload
const responseNonceAsBase64 = Utils.toBase64(responseReader.read(32));
if (responseNonceAsBase64 !== requestNonceAsBase64) {
return;
}
peerToUse.peer.stopListeningForGeneralMessages(listenerId);
// Save the identity key for the peer for future requests, since we have it here.
this.peers[baseURL].identityKey = senderPublicKey;
this.peers[baseURL].supportsMutualAuth = true;
// Status code
const statusCode = responseReader.readVarIntNum();
// Headers
const responseHeaders = {};
const nHeaders = responseReader.readVarIntNum();
if (nHeaders > 0) {
for (let i = 0; i < nHeaders; i++) {
const nHeaderKeyBytes = responseReader.readVarIntNum();
const headerKeyBytes = responseReader.read(nHeaderKeyBytes);
const headerKey = Utils.toUTF8(headerKeyBytes);
const nHeaderValueBytes = responseReader.readVarIntNum();
const headerValueBytes = responseReader.read(nHeaderValueBytes);
const headerValue = Utils.toUTF8(headerValueBytes);
responseHeaders[headerKey] = headerValue;
}
}
// Add back the server identity key header
responseHeaders['x-bsv-auth-identity-key'] = senderPublicKey;
// Body
let responseBody;
const responseBodyBytes = responseReader.readVarIntNum();
if (responseBodyBytes > 0) {
responseBody = responseReader.read(responseBodyBytes);
}
// Create the Response object
const responseValue = new Response(responseBody ? new Uint8Array(responseBody) : null, {
status: statusCode,
statusText: `${statusCode}`,
headers: new Headers(responseHeaders)
});
// Resolve or reject the correct request with the response data
this.callbacks[requestNonceAsBase64].resolve(responseValue);
// Clean up
delete this.callbacks[requestNonceAsBase64];
});
// Before sending general messages to the peer, ensure that no certificate requests are pending.
// This way, the user would need to choose to either allow or reject the certificate request first.
// If the server has a resource that requires certificates to be sent before access would be granted,
// this makes sure the user has a chance to send the certificates before the resource is requested.
if (peerToUse.pendingCertificateRequests.length > 0) {
await new Promise(resolve => {
setInterval(() => {
if (peerToUse.pendingCertificateRequests.length === 0) {
resolve();
}
}, 100); // Check every 100 ms for the user to finish responding
});
}
// Send the request, now that all listeners are set up
await peerToUse.peer.toPeer(writer.toArray(), peerToUse.identityKey).catch(async (error) => {
if (error.message.includes('Session not found for nonce')) {
delete this.peers[baseURL];
config.retryCounter ??= 3;
const response = await this.fetch(url, config);
resolve(response);
return;
}
if (error.message.includes('HTTP server failed to authenticate')) {
try {
const response = await this.handleFetchAndValidate(url, config, peerToUse);
resolve(response);
return;
}
catch (fetchError) {
reject(fetchError);
}
}
else {
reject(error);
}
});
}
catch (e) {
reject(e);
}
}));
// Check if server requires payment to access the requested route
if (response.status === 402) {
// Create and attach a payment, then retry
return await this.handlePaymentAndRetry(url, config, response);
}
return response;
}
/**
* Request Certificates from a Peer
* @param baseUrl
* @param certificatesToRequest
*/
async sendCertificateRequest(baseUrl, certificatesToRequest) {
const parsedUrl = new URL(baseUrl);
const baseURL = parsedUrl.origin;
let peerToUse;
if (typeof this.peers[baseURL] !== 'undefined') {
peerToUse = { peer: this.peers[baseURL].peer };
}
else {
const newTransport = new SimplifiedFetchTransport(baseURL);
peerToUse = {
peer: new Peer(this.wallet, newTransport, this.requestedCertificates, this.sessionManager, this.originator)
};
this.peers[baseURL] = peerToUse;
}
// Return a promise that resolves when certificates are received
return await new Promise((async (resolve, reject) => {
// Set up the listener before making the request
const callbackId = peerToUse.peer.listenForCertificatesReceived((_senderPublicKey, certs) => {
peerToUse.peer.stopListeningForCertificatesReceived(callbackId);
this.certificatesReceived.push(...certs);
resolve(certs);
});
try {
// Initiate the certificate request
await peerToUse.peer.requestCertificates(certificatesToRequest, peerToUse.identityKey);
}
catch (err) {
peerToUse.peer.stopListeningForCertificatesReceived(callbackId);
reject(err);
}
}));
}
/**
* Return any certificates we've collected thus far, then clear them out.
*/
consumeReceivedCertificates() {
return this.certificatesReceived.splice(0);
}
/**
* Serializes the HTTP request to be sent over the Transport.
*
* @param method - The HTTP method (e.g., 'GET', 'POST') for the request.
* @param headers - A record of HTTP headers to include in the request.
* @param body - The body of the request, if applicable (e.g., for POST/PUT requests).
* @param parsedUrl - The parsed URL object containing the full request URL.
* @param requestNonce - A unique random nonce to ensure request integrity.
* @returns A promise that resolves to a `Writer` containing the serialized request.
*
* @throws Will throw an error if unsupported headers are used or serialization fails.
*/
async serializeRequest(method, headers, body, parsedUrl, requestNonce) {
const writer = new Utils.Writer();
// Write request nonce
writer.write(requestNonce);
// Method length
writer.writeVarIntNum(method.length);
// Method
writer.write(Utils.toArray(method));
// Handle pathname (e.g. /path/to/resource)
if (parsedUrl.pathname.length > 0) {
// Pathname length
const pathnameAsArray = Utils.toArray(parsedUrl.pathname);
writer.writeVarIntNum(pathnameAsArray.length);
// Pathname
writer.write(pathnameAsArray);
}
else {
writer.writeVarIntNum(-1);
}
// Handle search params (e.g. ?q=hello)
if (parsedUrl.search.length > 0) {
// search length
const searchAsArray = Utils.toArray(parsedUrl.search);
writer.writeVarIntNum(searchAsArray.length);
// search
writer.write(searchAsArray);
}
else {
writer.writeVarIntNum(-1);
}
// Construct headers to send / sign:
// Ensures clients only provided supported HTTP request headers
// - Include custom headers prefixed with x-bsv (excluding those starting with x-bsv-auth)
// - Include a normalized version of the content-type header
// - Include the authorization header
const includedHeaders = [];
for (let [k, v] of Object.entries(headers)) {
k = k.toLowerCase(); // We will always sign lower-case header keys
if (k.startsWith('x-bsv-') || k === 'authorization') {
if (k.startsWith('x-bsv-auth')) {
throw new Error('No BSV auth headers allowed here!');
}
includedHeaders.push([k, v]);
}
else if (k.startsWith('content-type')) {
// Normalize the Content-Type header by removing any parameters (e.g., "; charset=utf-8")
v = v.split(';')[0].trim();
includedHeaders.push([k, v]);
}
else {
throw new Error('Unsupported header in the simplified fetch implementation. Only content-type, authorization, and x-bsv-* headers are supported.');
}
}
// Sort the headers by key to ensure a consistent order for signing and verification.
includedHeaders.sort(([keyA], [keyB]) => keyA.localeCompare(keyB));
// nHeaders
writer.writeVarIntNum(includedHeaders.length);
for (let i = 0; i < includedHeaders.length; i++) {
// headerKeyLength
const headerKeyAsArray = Utils.toArray(includedHeaders[i][0], 'utf8');
writer.writeVarIntNum(headerKeyAsArray.length);
// headerKey
writer.write(headerKeyAsArray);
// headerValueLength
const headerValueAsArray = Utils.toArray(includedHeaders[i][1], 'utf8');
writer.writeVarIntNum(headerValueAsArray.length);
// headerValue
writer.write(headerValueAsArray);
}
// If method typically carries a body and body is undefined, default it
// This prevents signature verification errors due to mismatch default body types with express
const methodsThatTypicallyHaveBody = ['POST', 'PUT', 'PATCH', 'DELETE'];
if (methodsThatTypicallyHaveBody.includes(method.toUpperCase()) && body === undefined) {
// Check if content-type is application/json
const contentTypeHeader = includedHeaders.find(([k]) => k === 'content-type');
if (contentTypeHeader && contentTypeHeader[1].includes('application/json')) {
body = '{}';
}
else {
body = '';
}
}
// Handle body
if (body) {
const reqBody = await this.normalizeBodyToNumberArray(body); // Use the utility function
writer.writeVarIntNum(reqBody.length);
writer.write(reqBody);
}
else {
writer.writeVarIntNum(-1); // No body
}
return writer;
}
/**
* Handles a non-authenticated fetch requests and validates that the server is not claiming to be authenticated.
*/
async handleFetchAndValidate(url, config, peerToUse) {
const response = await fetch(url, config);
response.headers.forEach(header => {
if (header.toLocaleLowerCase().startsWith('x-bsv')) {
throw new Error('The server is trying to claim it has been authenticated when it has not!');
}
});
if (response.ok) {
peerToUse.supportsMutualAuth = false;
return response;
}
else {
throw new Error(`Request failed with status: ${response.status}`);
}
}
/**
* If we get 402 Payment Required, we build a transaction via wallet.createAction()
* and re-attempt the request with an x-bsv-payment header.
*/
async handlePaymentAndRetry(url, config = {}, originalResponse) {
// Make sure the server is using the correct payment version
const paymentVersion = originalResponse.headers.get('x-bsv-payment-version');
if (!paymentVersion || paymentVersion !== PAYMENT_VERSION) {
throw new Error(`Unsupported x-bsv-payment-version response header. Client version: ${PAYMENT_VERSION}, Server version: ${paymentVersion}`);
}
// Get required headers from the 402 response
const satoshisRequiredHeader = originalResponse.headers.get('x-bsv-payment-satoshis-required');
if (!satoshisRequiredHeader) {
throw new Error('Missing x-bsv-payment-satoshis-required response header.');
}
const satoshisRequired = parseInt(satoshisRequiredHeader);
if (isNaN(satoshisRequired) || satoshisRequired <= 0) {
throw new Error('Invalid x-bsv-payment-satoshis-required response header value.');
}
const serverIdentityKey = originalResponse.headers.get('x-bsv-auth-identity-key');
if (typeof serverIdentityKey !== 'string') {
throw new Error('Missing x-bsv-auth-identity-key response header.');
}
const derivationPrefix = originalResponse.headers.get('x-bsv-payment-derivation-prefix');
if (typeof derivationPrefix !== 'string' || derivationPrefix.length < 1) {
throw new Error('Missing x-bsv-payment-derivation-prefix response header.');
}
// Create a random suffix for the derivation path
const derivationSuffix = await createNonce(this.wallet, undefined, this.originator);
// Derive the script hex from the server identity key
const { publicKey: derivedPublicKey } = await this.wallet.getPublicKey({
protocolID: [2, '3241645161d8'],
keyID: `${derivationPrefix} ${derivationSuffix}`,
counterparty: serverIdentityKey
}, this.originator);
const lockingScript = new P2PKH().lock(PublicKey.fromString(derivedPublicKey).toAddress()).toHex();
// Create the payment transaction using createAction
const { tx } = await this.wallet.createAction({
description: `Payment for request to ${new URL(url).origin}`,
outputs: [{
satoshis: satoshisRequired,
lockingScript,
customInstructions: JSON.stringify({ derivationPrefix, derivationSuffix, payee: serverIdentityKey }),
outputDescription: 'HTTP request payment'
}],
options: {
randomizeOutputs: false
}
}, this.originator);
// Attach the payment to the request headers
config.headers = config.headers || {};
config.headers['x-bsv-payment'] = JSON.stringify({
derivationPrefix,
derivationSuffix,
transaction: Utils.toBase64(tx)
});
config.retryCounter ??= 3;
// Re-attempt request with payment attached
return this.fetch(url, config);
}
async normalizeBodyToNumberArray(body) {
// 0. Null / undefined
if (body == null) {
return [];
}
// 1. object
if (typeof body === 'object') {
return Utils.toArray(JSON.stringify(body, 'utf8'));
}
// 2. number[]
if (Array.isArray(body) && body.every((item) => typeof item === 'number')) {
return body; // Return the array as is
}
// 3. string
if (typeof body === 'string') {
return Utils.toArray(body, 'utf8');
}
// 4. ArrayBuffer / TypedArrays
if (body instanceof ArrayBuffer || ArrayBuffer.isView(body)) {
const typedArray = body instanceof ArrayBuffer ? new Uint8Array(body) : new Uint8Array(body.buffer);
return Array.from(typedArray);
}
// 5. Blob
if (body instanceof Blob) {
const arrayBuffer = await body.arrayBuffer();
return Array.from(new Uint8Array(arrayBuffer));
}
// 6. FormData
if (body instanceof FormData) {
const entries = [];
body.forEach((value, key) => {
entries.push([key, value.toString()]);
});
const urlEncoded = new URLSearchParams(entries).toString();
return Utils.toArray(urlEncoded, 'utf8');
}
// 7. URLSearchParams
if (body instanceof URLSearchParams) {
return Utils.toArray(body.toString(), 'utf8');
}
// 8. ReadableStream
if (body instanceof ReadableStream) {
throw new Error('ReadableStream cannot be directly converted to number[].');
}
// 9. Fallback
throw new Error('Unsupported body type in this SimplifiedFetch implementation.');
}
}
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