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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this file,
import { Log } from "resource://gre/modules/Log.sys.mjs";
const PREF_LOG_LEVEL = "services.common.log.logger.tokenserverclient";
/**
* Represents a TokenServerClient error that occurred on the client.
*
* This is the base type for all errors raised by client operations.
*
* @param message
* (string) Error message.
*/
export function TokenServerClientError(message) {
this.name = "TokenServerClientError";
this.message = message || "Client error.";
// Without explicitly setting .stack, all stacks from these errors will point
// to the "new Error()" call a few lines down, which isn't helpful.
this.stack = Error().stack;
}
TokenServerClientError.prototype = new Error();
TokenServerClientError.prototype.constructor = TokenServerClientError;
TokenServerClientError.prototype._toStringFields = function () {
return { message: this.message };
};
TokenServerClientError.prototype.toString = function () {
return this.name + "(" + JSON.stringify(this._toStringFields()) + ")";
};
TokenServerClientError.prototype.toJSON = function () {
let result = this._toStringFields();
result.name = this.name;
return result;
};
/**
* Represents a TokenServerClient error that occurred in the network layer.
*
* @param error
* The underlying error thrown by the network layer.
*/
export function TokenServerClientNetworkError(error) {
this.name = "TokenServerClientNetworkError";
this.error = error;
this.stack = Error().stack;
}
TokenServerClientNetworkError.prototype = new TokenServerClientError();
TokenServerClientNetworkError.prototype.constructor =
TokenServerClientNetworkError;
TokenServerClientNetworkError.prototype._toStringFields = function () {
return { error: this.error };
};
/**
* Represents a TokenServerClient error that occurred on the server.
*
* This type will be encountered for all non-200 response codes from the
* server. The type of error is strongly enumerated and is stored in the
* `cause` property. This property can have the following string values:
*
* invalid-credentials -- A token could not be obtained because
* the credentials presented by the client were invalid.
*
* unknown-service -- The requested service was not found.
*
* malformed-request -- The server rejected the request because it
* was invalid. If you see this, code in this file is likely wrong.
*
* malformed-response -- The response from the server was not what was
* expected.
*
* general -- A general server error has occurred. Clients should
* interpret this as an opaque failure.
*
* @param message
* (string) Error message.
*/
export function TokenServerClientServerError(message, cause = "general") {
this.now = new Date().toISOString(); // may be useful to diagnose time-skew issues.
this.name = "TokenServerClientServerError";
this.message = message || "Server error.";
this.cause = cause;
this.stack = Error().stack;
}
TokenServerClientServerError.prototype = new TokenServerClientError();
TokenServerClientServerError.prototype.constructor =
TokenServerClientServerError;
TokenServerClientServerError.prototype._toStringFields = function () {
let fields = {
now: this.now,
message: this.message,
cause: this.cause,
};
if (this.response) {
fields.response_body = this.response.body;
fields.response_headers = this.response.headers;
fields.response_status = this.response.status;
}
return fields;
};
/**
* Represents a client to the Token Server.
*
*
* The Token Server was designed to support obtaining tokens for arbitrary apps by
* constructing URI paths of the form <app>/<app_version>. In practice this was
* never used and it only supports an <app> value of `sync`, and the API presented
* here reflects that.
*
* Areas to Improve:
*
* - The server sends a JSON response on error. The client does not currently
* parse this. It might be convenient if it did.
* - Currently most non-200 status codes are rolled into one error type. It
* might be helpful if callers had a richer API that communicated who was
* at fault (e.g. differentiating a 503 from a 401).
*/
export function TokenServerClient() {
this._log = Log.repository.getLogger("Services.Common.TokenServerClient");
this._log.manageLevelFromPref(PREF_LOG_LEVEL);
}
TokenServerClient.prototype = {
/**
* Logger instance.
*/
_log: null,
/**
* Obtain a token from a provided OAuth token against a specific URL.
*
* This asynchronously obtains the token.
* It returns a Promise that resolves or rejects:
*
* Rejects with:
* (TokenServerClientError) If no token could be obtained, this
* will be a TokenServerClientError instance describing why. The
* type seen defines the type of error encountered. If an HTTP response
* was seen, a RESTResponse instance will be stored in the `response`
* property of this object. If there was no error and a token is
* available, this will be null.
*
* Resolves with:
* (map) On success, this will be a map containing the results from
* the server. If there was an error, this will be null. The map has the
* following properties:
*
* id (string) HTTP MAC public key identifier.
* key (string) HTTP MAC shared symmetric key.
* endpoint (string) URL where service can be connected to.
* uid (string) user ID for requested service.
* duration (string) the validity duration of the issued token.
*
* Example Usage
* -------------
*
* let client = new TokenServerClient();
* let access_token = getOAuthAccessTokenFromSomewhere();
*
* try {
* const result = await client.getTokenUsingOAuth(url, access_token);
* let {id, key, uid, endpoint, duration} = result;
* // Do stuff with data and carry on.
* } catch (error) {
* // Handle errors.
* }
* Obtain a token from a provided OAuth token against a specific URL.
*
* @param url
* (string) URL to fetch token from.
* @param oauthToken
* (string) FxA OAuth Token to exchange token for.
* @param addHeaders
* (object) Extra headers for the request.
*/
async getTokenUsingOAuth(url, oauthToken, addHeaders = {}) {
this._log.debug("Beginning OAuth token exchange: " + url);
if (!oauthToken) {
throw new TokenServerClientError("oauthToken argument is not valid.");
}
return this._tokenServerExchangeRequest(
url,
`Bearer ${oauthToken}`,
addHeaders
);
},
/**
* Performs the exchange request to the token server to
* produce a token based on the authorizationHeader input.
*
* @param url
* (string) URL to fetch token from.
* @param authorizationHeader
* (string) The auth header string that populates the 'Authorization' header.
* @param addHeaders
* (object) Extra headers for the request.
*/
async _tokenServerExchangeRequest(url, authorizationHeader, addHeaders = {}) {
if (!url) {
throw new TokenServerClientError("url argument is not valid.");
}
if (!authorizationHeader) {
throw new TokenServerClientError(
"authorizationHeader argument is not valid."
);
}
let req = this.newRESTRequest(url);
req.setHeader("Accept", "application/json");
req.setHeader("Authorization", authorizationHeader);
for (let header in addHeaders) {
req.setHeader(header, addHeaders[header]);
}
let response;
try {
response = await req.get();
} catch (err) {
throw new TokenServerClientNetworkError(err);
}
try {
return this._processTokenResponse(response);
} catch (ex) {
if (ex instanceof TokenServerClientServerError) {
throw ex;
}
this._log.warn("Error processing token server response", ex);
let error = new TokenServerClientError(ex);
error.response = response;
throw error;
}
},
/**
* Handler to process token request responses.
*
* @param response
* RESTResponse from token HTTP request.
*/
_processTokenResponse(response) {
this._log.debug("Got token response: " + response.status);
// Responses should *always* be JSON, even in the case of 4xx and 5xx
// errors. If we don't see JSON, the server is likely very unhappy.
let ct = response.headers["content-type"] || "";
if (ct != "application/json" && !ct.startsWith("application/json;")) {
this._log.warn("Did not receive JSON response. Misconfigured server?");
this._log.debug("Content-Type: " + ct);
this._log.debug("Body: " + response.body);
let error = new TokenServerClientServerError(
"Non-JSON response.",
"malformed-response"
);
error.response = response;
throw error;
}
let result;
try {
result = JSON.parse(response.body);
} catch (ex) {
this._log.warn("Invalid JSON returned by server: " + response.body);
let error = new TokenServerClientServerError(
"Malformed JSON.",
"malformed-response"
);
error.response = response;
throw error;
}
// Any response status can have X-Backoff or X-Weave-Backoff headers.
this._maybeNotifyBackoff(response, "x-weave-backoff");
this._maybeNotifyBackoff(response, "x-backoff");
// The service shouldn't have any 3xx, so we don't need to handle those.
if (response.status != 200) {
// We /should/ have a Cornice error report in the JSON. We log that to
// help with debugging.
if ("errors" in result) {
// This could throw, but this entire function is wrapped in a try. If
// the server is sending something not an array of objects, it has
// failed to keep its contract with us and there is little we can do.
for (let error of result.errors) {
this._log.info("Server-reported error: " + JSON.stringify(error));
}
}
let error = new TokenServerClientServerError();
error.response = response;
if (response.status == 400) {
error.message = "Malformed request.";
error.cause = "malformed-request";
} else if (response.status == 401) {
// Cause can be invalid-credentials, invalid-timestamp, or
// invalid-generation.
error.message = "Authentication failed.";
error.cause = result.status;
} else if (response.status == 404) {
error.message = "Unknown service.";
error.cause = "unknown-service";
}
// A Retry-After header should theoretically only appear on a 503, but
// we'll look for it on any error response.
this._maybeNotifyBackoff(response, "retry-after");
throw error;
}
for (let k of ["id", "key", "api_endpoint", "uid", "duration"]) {
if (!(k in result)) {
let error = new TokenServerClientServerError(
"Expected key not present in result: " + k
);
error.cause = "malformed-response";
error.response = response;
throw error;
}
}
this._log.debug("Successful token response");
return {
id: result.id,
key: result.key,
endpoint: result.api_endpoint,
uid: result.uid,
duration: result.duration,
hashed_fxa_uid: result.hashed_fxa_uid,
node_type: result.node_type,
};
},
/*
* The prefix used for all notifications sent by this module. This
* allows the handler of notifications to be sure they are handling
* notifications for the service they expect.
*
* If not set, no notifications will be sent.
*/
observerPrefix: null,
// Given an optional header value, notify that a backoff has been requested.
_maybeNotifyBackoff(response, headerName) {
if (!this.observerPrefix) {
return;
}
let headerVal = response.headers[headerName];
if (!headerVal) {
return;
}
let backoffInterval;
try {
backoffInterval = parseInt(headerVal, 10);
} catch (ex) {
this._log.error(
"TokenServer response had invalid backoff value in '" +
headerName +
"' header: " +
headerVal
);
return;
}
Observers.notify(
this.observerPrefix + ":backoff:interval",
backoffInterval
);
},
// override points for testing.
newRESTRequest(url) {
return new RESTRequest(url);
},
};