feat(frontend): hosted sign-in and OAuth settings for Cognito app clients

packages/api/src/adapter-aws/AwsUserPoolsAdapter.ts

@@ -24,11 +24,13 @@ import {
     ListUserPoolClientsCommand,
     ListUserPoolsCommand,
     ListUsersCommand,
+    UpdateUserPoolClientCommand,
     type AttributeType,
     type CognitoIdentityProviderClient,
     type GroupType,
     type PasswordPolicyType,
     type UserPoolClientDescription,
+    type UserPoolClientType,
     type UserPoolDescriptionType,
     type UserPoolType,
     type UserType,
@@ -38,6 +40,7 @@ import {ConflictError, RuntimeError, ValidationError} from '../cloud-spi/errors'
 import {
     USER_POOL_GROUP_NAME_PATTERN,
     USER_POOL_NAME_PATTERN,
+    USER_POOL_OAUTH_FLOWS,
     USER_POOL_PASSWORD_POLICIES,
     USER_POOL_SIGN_IN,
     awsUserPoolsSchema,
@@ -49,7 +52,10 @@ import type {
     CreateUserPoolGroupInput,
     ResourceQuery,
     ServiceSchema,
+    UpdateUserPoolClientOAuthInput,
+    UserPoolClientSettings,
     UserPoolGroup,
+    UserPoolOAuthFlow,
     UserPoolSignInTestInput,
     UserPoolSignInTestResult,
     UserPoolUserAction,
@@ -285,6 +291,54 @@ export class AwsUserPoolsAdapter implements CloudServiceAdapter {
         }
     }
 
+    async describeUserPoolClient(poolId: string, clientId: string): Promise<UserPoolClientSettings> {
+        return toClientSettings(await this.fetchClient(poolId, clientId))
+    }
+
+    /**
+     * Changes the settings the hosted login and OAuth endpoints use. UpdateUserPoolClient
+     * resets every setting it is not given, so the client's other settings are sent back as they are.
+     */
+    async updateUserPoolClientOAuth(poolId: string, clientId: string, input: UpdateUserPoolClientOAuthInput): Promise<UserPoolClientSettings> {
+        const settings = validateOAuthSettings(input)
+        const current = await this.fetchClient(poolId, clientId)
+        if (settings.oauthFlows.includes('client_credentials') && !current.ClientSecret) {
+            throw new ValidationError('The client_credentials flow needs an app client with a secret')
+        }
+        const res = await this.cognito.send(new UpdateUserPoolClientCommand({
+            UserPoolId: poolId,
+            ClientId: clientId,
+            ClientName: current.ClientName,
+            RefreshTokenValidity: current.RefreshTokenValidity,
+            AccessTokenValidity: current.AccessTokenValidity,
+            IdTokenValidity: current.IdTokenValidity,
+            TokenValidityUnits: current.TokenValidityUnits,
+            ReadAttributes: current.ReadAttributes,
+            WriteAttributes: current.WriteAttributes,
+            ExplicitAuthFlows: current.ExplicitAuthFlows,
+            DefaultRedirectURI: current.DefaultRedirectURI && settings.callbackUrls.includes(current.DefaultRedirectURI) ? current.DefaultRedirectURI : undefined,
+            AnalyticsConfiguration: current.AnalyticsConfiguration,
+            PreventUserExistenceErrors: current.PreventUserExistenceErrors,
+            EnableTokenRevocation: current.EnableTokenRevocation,
+            EnablePropagateAdditionalUserContextData: current.EnablePropagateAdditionalUserContextData,
+            AuthSessionValidity: current.AuthSessionValidity,
+            RefreshTokenRotation: current.RefreshTokenRotation,
+            CallbackURLs: settings.callbackUrls,
+            LogoutURLs: settings.logoutUrls,
+            AllowedOAuthFlows: settings.oauthFlows,
+            AllowedOAuthScopes: settings.oauthScopes,
+            AllowedOAuthFlowsUserPoolClient: settings.oauthFlows.length > 0,
+            SupportedIdentityProviders: settings.identityProviders,
+        }))
+        return toClientSettings(res.UserPoolClient ?? current)
+    }
+
+    private async fetchClient(poolId: string, clientId: string): Promise<UserPoolClientType> {
+        const res = await this.cognito.send(new DescribeUserPoolClientCommand({UserPoolId: poolId, ClientId: requiredString(clientId, 'clientId')}))
+        if (!res.UserPoolClient) throw new RuntimeError(`Cognito returned no app client ${clientId}`)
+        return res.UserPoolClient
+    }
+
     private async listGroupsForUser(poolId: string, username: string): Promise<string[]> {
         return listGroupNamesForUser(this.cognito, poolId, username)
     }
@@ -497,6 +551,66 @@ function lambdaTriggersOf(config: UserPoolType['LambdaConfig']): LambdaTrigger[]
     })
 }
 
+function toClientSettings(client: UserPoolClientType): UserPoolClientSettings {
+    return {
+        clientId: client.ClientId ?? '',
+        clientName: client.ClientName ?? '',
+        hasSecret: Boolean(client.ClientSecret),
+        explicitAuthFlows: client.ExplicitAuthFlows ?? [],
+        callbackUrls: client.CallbackURLs ?? [],
+        logoutUrls: client.LogoutURLs ?? [],
+        oauthFlows: client.AllowedOAuthFlowsUserPoolClient ? (client.AllowedOAuthFlows ?? []).filter(isOAuthFlow) : [],
+        oauthScopes: client.AllowedOAuthScopes ?? [],
+        identityProviders: client.SupportedIdentityProviders ?? [],
+    }
+}
+
+function isOAuthFlow(value: string): value is UserPoolOAuthFlow {
+    return (USER_POOL_OAUTH_FLOWS as readonly string[]).includes(value)
+}
+
+/** Cognito's own rules for these settings, checked here so the form can say what is wrong. */
+function validateOAuthSettings(input: UpdateUserPoolClientOAuthInput): UpdateUserPoolClientOAuthInput {
+    const callbackUrls = urlList(input?.callbackUrls, 'Callback URL')
+    const logoutUrls = urlList(input.logoutUrls, 'Sign-out URL')
+    const oauthFlows = stringList(input.oauthFlows, 'oauthFlows')
+    const unknown = oauthFlows.find((flow) => !isOAuthFlow(flow))
+    if (unknown) throw new ValidationError(`Unknown OAuth flow ${unknown}`)
+    if (oauthFlows.includes('client_credentials') && oauthFlows.length > 1) {
+        throw new ValidationError('client_credentials cannot be combined with the code or implicit flows')
+    }
+    if ((oauthFlows.includes('code') || oauthFlows.includes('implicit')) && callbackUrls.length === 0) {
+        throw new ValidationError('Add at least one callback URL for the code or implicit flow')
+    }
+    const oauthScopes = stringList(input.oauthScopes, 'oauthScopes')
+    if (oauthFlows.length > 0 && oauthScopes.length === 0) throw new ValidationError('Choose at least one OAuth scope')
+    const identityProviders = stringList(input.identityProviders, 'identityProviders')
+    return {callbackUrls, logoutUrls, oauthFlows: oauthFlows as UserPoolOAuthFlow[], oauthScopes, identityProviders}
+}
+
+function stringList(value: unknown, field: string): string[] {
+    if (!Array.isArray(value) || value.some((entry) => typeof entry !== 'string')) throw new ValidationError(`${field} must be a list of strings`)
+    return [...new Set(value.map((entry: string) => entry.trim()).filter(Boolean))]
+}
+
+// Cognito accepts https URLs, and http only for localhost; fragments are never allowed.
+function urlList(value: unknown, label: string): string[] {
+    return stringList(value, label).map((entry) => {
+        let url: URL
+        try {
+            url = new URL(entry)
+        } catch {
+            throw new ValidationError(`${label} ${entry} is not a valid URL`)
+        }
+        const local = url.hostname === 'localhost' || url.hostname === '127.0.0.1'
+        if (url.protocol !== 'https:' && !(url.protocol === 'http:' && local)) {
+            throw new ValidationError(`${label} ${entry} must use https (http is allowed only for localhost)`)
+        }
+        if (url.hash || entry.includes('#')) throw new ValidationError(`${label} ${entry} must not contain a fragment`)
+        return entry
+    })
+}
+
 function toUserItem(
     username: string | undefined,
     attributes: AttributeType[] | undefined,