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package com.dropbox.core;

import static com.dropbox.core.util.StringUtil.jq;

import java.nio.charset.Charset;
import java.security.SecureRandom;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import com.dropbox.core.http.HttpRequestor;
import com.dropbox.core.util.StringUtil;
import com.dropbox.core.v2.DbxRawClientV2;

/*>>> import checkers.nullness.quals.Nullable; */

/**
 * Does the OAuth 2 "authorization code" flow.  (This SDK does not support the "token" flow.)
 *
 * 

Eventually yields an access token, which can be used with {@link * com.dropbox.core.v2.DbxClientV2} to make Dropbox API calls. You typically only need to do this * for a user when they first use your application. Once you have an access token for that user, it * remains valid for years. * *

Redirect example

*

One-time setup typically done on server initialization:

*
 *     {@link DbxRequestConfig} requestConfig = new DbxRequestConfig("text-edit/0.1");
 *     {@link DbxAppInfo} appInfo = DbxAppInfo.Reader.readFromFile("api.app");
 *     DbxWebAuth auth = new DbxWebAuth(requestConfig, appInfo);
 *
 *     String redirectUri = "http://my-server.com/dropbox-auth-finish";
 * 
* *

Part 1

*

Handler for "http://my-server.com/dropbox-auth-start":

*
 *     {@link javax.servlet.http.HttpServletRequest} request = ...
 *     {@link javax.servlet.http.HttpServletResponse} response = ...
 *
 *     // Select a spot in the session for DbxWebAuth to store the CSRF token.
 *     {@link javax.servlet.http.HttpSession} session = request.getSession(true);
 *     String sessionKey = "dropbox-auth-csrf-token";
 *     {@link DbxSessionStore} csrfTokenStore = new DbxStandardSessionStore(session, sessionKey);
 *
 *     // Build an auth request
 *     {@link DbxWebAuth.Request} authRequest = DbxWebAuth.newRequestBuilder()
 *         .withRedirectUri(redirectUri, csrfTokenStore)
 *         .build();
 *
 *     // Start authorization.
 *     String authorizePageUrl = auth.{@link #authorize authorize}(authRequest);
 *
 *     // Redirect the user to the Dropbox website so they can approve our application.
 *     // The Dropbox website will send them back to "http://my-server.com/dropbox-auth-finish"
 *     // when they're done.
 *     response.sendRedirect(authorizePageUrl);
 * 
* *

Part 2

*

Handler for "http://my-server.com/dropbox-auth-finish":

*
 *     {@link javax.servlet.http.HttpServletRequest} request = ...
 *     {@link javax.servlet.http.HttpServletResponse} response = ...
 *
 *     // Fetch the session to verify our CSRF token
 *     {@link javax.servlet.http.HttpSession} session = request.getSession(true);
 *     String sessionKey = "dropbox-auth-csrf-token";
 *     {@link DbxSessionStore} csrfTokenStore = new DbxStandardSessionStore(session, sessionKey);
 *     String redirectUri = "http://my-server.com/dropbox-auth-finish";
 *
 *     {@link DbxAuthFinish} authFinish;
 *     try {
 *         authFinish = auth.{@link #finishFromRedirect finishFromRedirect}(redirectUri, csrfTokenStore, request.getParameterMap());
 *     } catch (DbxWebAuth.BadRequestException ex) {
 *         log("On /dropbox-auth-finish: Bad request: " + ex.getMessage());
 *         response.sendError(400);
 *         return;
 *     } catch (DbxWebAuth.BadStateException ex) {
 *         // Send them back to the start of the auth flow.
 *         response.sendRedirect("http://my-server.com/dropbox-auth-start");
 *         return;
 *     } catch (DbxWebAuth.CsrfException ex) {
 *         log("On /dropbox-auth-finish: CSRF mismatch: " + ex.getMessage());
 *         response.sendError(403, "Forbidden.");
 *         return;
 *     } catch (DbxWebAuth.NotApprovedException ex) {
 *         // When Dropbox asked "Do you want to allow this app to access your
 *         // Dropbox account?", the user clicked "No".
 *         ...
 *         return;
 *     } catch (DbxWebAuth.ProviderException ex) {
 *         log("On /dropbox-auth-finish: Auth failed: " + ex.getMessage());
 *         response.sendError(503, "Error communicating with Dropbox.");
 *         return;
 *     } catch (DbxException ex) {
 *         log("On /dropbox-auth-finish: Error getting token: " + ex.getMessage());
 *         response.sendError(503, "Error communicating with Dropbox.");
 *         return;
 *     }
 *     String accessToken = authFinish.getAccessToken();
 *
 *     // Save the access token somewhere (probably in your database) so you
 *     // don't need to send the user through the authorization process again.
 *     ...
 *
 *     // Now use the access token to make Dropbox API calls.
 *     {@link com.dropbox.core.v2.DbxClientV2} client = new DbxClientV2(requestConfig, accessToken);
 *     ...
 * 
* *

No Redirect Example

* *
 *     {@link DbxRequestConfig} requestConfig = new DbxRequestConfig("text-edit/0.1");
 *     {@link DbxAppInfo} appInfo = DbxAppInfo.Reader.readFromFile("api.app");
 *     DbxWebAuth auth = new DbxWebAuth(requestConfig, appInfo);
 *
 *     {@link DbxWebAuth.Request} authRequest = DbxWebAuth.newRequestBuilder()
 *         .withNoRedirect()
 *         .build();
 *     String authorizeUrl = auth.authorize(authRequest);
 *     System.out.println("1. Go to " + authorizeUrl);
 *     System.out.println("2. Click \"Allow\" (you might have to log in first).");
 *     System.out.println("3. Copy the authorization code.");
 *     System.out.print("Enter the authorization code here: ");
 *
 *     String code = System.console().readLine();
 *     if (code != null) {
 *         code = code.trim();
 *         {@link DbxAuthFinish} authFinish = webAuth.{@link #finishFromCode finishFromCode}(code);
 *         {@link com.dropbox.core.v2.DbxClientV2} client = new DbxClientV2(requestConfig, authFinish.getAccessToken());
 *     }
 * 
*/ public class DbxWebAuth { private static final SecureRandom RAND = new SecureRandom(); private static final int CSRF_BYTES_SIZE = 16; private static final int CSRF_STRING_SIZE = StringUtil.urlSafeBase64Encode(new byte[CSRF_BYTES_SIZE]).length(); /** Role representing the team account associated with a user. Used by {@link Request.Builder#withRequireRole}. */ public static final String ROLE_WORK = "work"; /** Role representing the personal account associated with a user. Used by {@link Request.Builder#withRequireRole}. */ public static final String ROLE_PERSONAL = "personal"; private final DbxRequestConfig requestConfig; private final DbxAppInfo appInfo; private final Request deprecatedRequest; /** * Creates a new instance that will perform the OAuth2 authorization flow using a redirect URI. * * @param requestConfig HTTP request configuration, never {@code null}. * @param appInfo Your application's Dropbox API information (the app key and secret), never * {@code nulL}. * @param redirectUri Where to redirect the user after authorization has completed, never {@code null}. * @param sessionStore Session store to use for storing CSRF nonces across requests, never {@code null}. * * @deprecated use {@link #DbxWebAuth(DbxRequestConfig,DbxAppInfo)} and {@link #authorize} * instead */ @Deprecated public DbxWebAuth(DbxRequestConfig requestConfig, DbxAppInfo appInfo, String redirectUri, DbxSessionStore sessionStore) { if (requestConfig == null) throw new NullPointerException("requestConfig"); if (appInfo == null) throw new NullPointerException("appInfo"); this.requestConfig = requestConfig; this.appInfo = appInfo; this.deprecatedRequest = newRequestBuilder() .withRedirectUri(redirectUri, sessionStore) .build(); } /** * Creates a new instance that will perform the OAuth2 authorization flow using the given OAuth * request configuration. * * @param requestConfig HTTP request configuration, never {@code null}. * @param appInfo Your application's Dropbox API information (the app key and secret), never * {@code null}. */ public DbxWebAuth(DbxRequestConfig requestConfig, DbxAppInfo appInfo) { if (requestConfig == null) throw new NullPointerException("requestConfig"); if (appInfo == null) throw new NullPointerException("appInfo"); this.requestConfig = requestConfig; this.appInfo = appInfo; this.deprecatedRequest = null; } /** * Starts authorization and returns a "authorization URL" on the Dropbox website that gives the * lets the user grant your app access to their Dropbox account. * *

If a redirect URI was specified, then users will be redirected to the redirect URI after * completing the authorization flow. Call {@link #finishFromRedirect finishFromRedirect(..)} with the query parameters * received from the redirect. * *

If no redirect URI was specified, then users who grant access will be shown an * "authorization code". The user must copy/paste the authorization code back into your app, at * which point you can call {@link #finishFromCode(String)} to get an access token. * * @param urlState additional state to add to the flow that will be returned upon redirect * * @throws IllegalArgumentException if urlState exceeds maximum size of 476 bytes * @throws IllegalStateException if this instance was not created using the deprecated {@link #DbxWebAuth(DbxRequestConfig,DbxAppInfo,String,DbxSessionStore)} constructor * * @return Authorization URL of website user can use to authorize your app. * * @deprecated use {@link #DbxWebAuth(DbxRequestConfig,DbxAppInfo)} and {@link #authorize} * instead. */ @Deprecated public String start(/*@Nullable*/String urlState) { if (deprecatedRequest == null) { throw new IllegalStateException("Must use DbxWebAuth.authorize instead."); } return authorizeImpl( deprecatedRequest.copy() .withState(urlState) .build() ); } /** * Starts authorization and returns a "authorization URL" on the Dropbox website that gives the * lets the user grant your app access to their Dropbox account. * *

If a redirect URI was specified ({@link Request.Builder#withRedirectUri}), then users * will be redirected to the redirect URI after completing the authorization flow. Call {@link * #finishFromRedirect} with the query parameters received from the redirect. * *

If no redirect URI was specified ({@link Request.Builder#withNoRedirect}), then users who * grant access will be shown an "authorization code". The user must copy/paste the * authorization code back into your app, at which point you can call {@link * #finishFromCode(String)} to get an access token. * * @param request OAuth 2.0 web-based authorization flow request configuration * * @return Authorization URL of website user can use to authorize your app. * * @throws IllegalStateException if this {@link DbxWebAuth} instance was created using the * deprecated {@link #DbxWebAuth(DbxRequestConfig,DbxAppInfo,String,DbxSessionStore)} * constructor. */ public String authorize(Request request) { if (deprecatedRequest != null) { throw new IllegalStateException("Must create this instance using DbxWebAuth(DbxRequestConfig,DbxAppInfo) to call this method."); } return authorizeImpl(request); } private String authorizeImpl(Request request) { Map params = new HashMap(); params.put("client_id", appInfo.getKey()); params.put("response_type", "code"); if (request.redirectUri != null) { params.put("redirect_uri", request.redirectUri); params.put("state", appendCsrfToken(request)); } if (request.requireRole != null) { params.put("require_role", request.requireRole); } if (request.forceReapprove != null) { params.put("force_reapprove", Boolean.toString(request.forceReapprove).toLowerCase()); } if (request.disableSignup != null) { params.put("disable_signup", Boolean.toString(request.disableSignup).toLowerCase()); } return DbxRequestUtil.buildUrlWithParams( requestConfig.getUserLocale(), appInfo.getHost().getWeb(), "oauth2/authorize", DbxRequestUtil.toParamsArray(params) ); } /** * Call this after the user has visited the authorizaton URL and copy/pasted the authorization * code that Dropbox gave them. * * @param code The authorization code shown to the user when they clicked "Allow" on the * authorization, page on the Dropbox website, never {@code null}. * * @throws DbxException if an error occurs communicating with Dropbox. */ public DbxAuthFinish finishFromCode(String code) throws DbxException { return finish(code); } /** * Call this after the user has visited the authorizaton URL with a redirectUrl and copy/pasted * the authorization code that Dropbox gave them. * * @param code The authorization code shown to the user when they clicked "Allow" on the * authorization, page on the Dropbox website, never {@code null}. * @param redirectUri The original redirect URI used by {@link #authorize}, never {@code null}. * * @throws DbxException if an error occurs communicating with Dropbox. */ public DbxAuthFinish finishFromCode(String code, String redirectUri) throws DbxException { return finish(code, redirectUri, null); } /** * Call this after the user has visited the authorizaton URL and Dropbox has redirected them * back to you at the redirect URI. * * @param redirectUri The original redirect URI used by {@link #authorize}, never {@code null}. * @param sessionStore Session store used by {@link #authorize} to store CSRF tokens, never * {@code null}. * @param params The query parameters on the GET request to your redirect URI, never {@code * null}. * * @throws BadRequestException If the redirect request is missing required query parameters, * contains duplicate parameters, or includes mutually exclusive parameters (e.g. {@code * "error"} and {@code "code"}). * @throws BadStateException If the CSRF token retrieved from {@code sessionStore} is {@code * null} or malformed. * @throws CsrfException If the CSRF token passed in {@code params} does not match the CSRF * token from {@code sessionStore}. This implies the redirect request may be forged. * @throws NotApprovedException If the user chose to deny the authorization request. * @throws ProviderException If an OAuth2 error response besides {@code "access_denied"} is * set. * @throws DbxException If an error occurs communicating with Dropbox. */ public DbxAuthFinish finishFromRedirect(String redirectUri, DbxSessionStore sessionStore, Map params) throws DbxException, BadRequestException, BadStateException, CsrfException, NotApprovedException, ProviderException { if (redirectUri == null) throw new NullPointerException("redirectUri"); if (sessionStore == null) throw new NullPointerException("sessionStore"); if (params == null) throw new NullPointerException("params"); String state = getParam(params, "state"); if (state == null) { throw new BadRequestException("Missing required parameter: \"state\"."); } String error = getParam(params, "error"); String code = getParam(params, "code"); String errorDescription = getParam(params, "error_description"); if (code == null && error == null) { throw new BadRequestException("Missing both \"code\" and \"error\"."); } if (code != null && error != null) { throw new BadRequestException("Both \"code\" and \"error\" are set."); } if (code != null && errorDescription != null) { throw new BadRequestException("Both \"code\" and \"error_description\" are set."); } state = verifyAndStripCsrfToken(state, sessionStore); if (error != null) { if (error.equals("access_denied")) { // User clicked "Deny" String exceptionMessage = errorDescription == null ? "No additional description from Dropbox" : "Additional description from Dropbox: " + errorDescription; throw new NotApprovedException(exceptionMessage); } else { // All other errors String exceptionMessage = errorDescription == null ? error : String.format("%s: %s", error, errorDescription); throw new ProviderException(exceptionMessage); } } return finish(code, redirectUri, state); } private DbxAuthFinish finish(String code) throws DbxException { return finish(code, null, null); } private DbxAuthFinish finish(String code, String redirectUri, final String state) throws DbxException { if (code == null) throw new NullPointerException("code"); Map params = new HashMap(); params.put("grant_type", "authorization_code"); params.put("code", code); params.put("locale", requestConfig.getUserLocale()); if (redirectUri != null) { params.put("redirect_uri", redirectUri); } List headers = new ArrayList(); DbxRequestUtil.addBasicAuthHeader(headers, appInfo.getKey(), appInfo.getSecret()); return DbxRequestUtil.doPostNoAuth( requestConfig, DbxRawClientV2.USER_AGENT_ID, appInfo.getHost().getApi(), "oauth2/token", DbxRequestUtil.toParamsArray(params), headers, new DbxRequestUtil.ResponseHandler() { @Override public DbxAuthFinish handle(HttpRequestor.Response response) throws DbxException { if (response.getStatusCode() != 200) { throw DbxRequestUtil.unexpectedStatus(response); } return DbxRequestUtil.readJsonFromResponse(DbxAuthFinish.Reader, response) .withUrlState(state); } } ); } /** * Call this after the user has visited the authorizaton URL and Dropbox has redirected them * back to you (using the {@code redirectUri} you passed in to {@link #start}. * * @param queryParams The query parameters on the GET request to your {@code redirectUri}. * * @throws IllegalStateException if this instance was not created using the deprecated {@link #DbxWebAuth(DbxRequestConfig,DbxAppInfo,String,DbxSessionStore)} constructor * @throws BadRequestException If the redirect request is missing required query parameters, * contains duplicate parameters, or includes mutually exclusive parameters (e.g. {@code * "error"} and {@code "code"}) * @throws BadStateException If the CSRF token retrieved from {@code sessionStore} is missing or * malformed. Missing tokens often imply the user session has expired. * @throws CsrfException If the CSRF token passed in {@code params} does not match the CSRF * token from {@code sessionStore}. This implies the redirect request may be forged. * @throws NotApprovedException If the user chose to deny the authorization request * @throws ProviderException If an OAuth 2.0 error response besides {@code "access_denied"} is * set. * @throws DbxException If an error occurs communicating with Dropbox * * @deprecated use {@link #finishFromRedirect finishFromRedirect(..)} instead. */ @Deprecated public DbxAuthFinish finish(Map queryParams) throws DbxException, BadRequestException, BadStateException, CsrfException, NotApprovedException, ProviderException { if (deprecatedRequest == null) { throw new IllegalStateException("Must use DbxWebAuth.finishFromRedirect(..) instead."); } return finishFromRedirect( deprecatedRequest.redirectUri, deprecatedRequest.sessionStore, queryParams ); } private static String appendCsrfToken(Request request) { // add a CSRF nonce for security byte[] csrf = new byte[CSRF_BYTES_SIZE]; RAND.nextBytes(csrf); String prefix = StringUtil.urlSafeBase64Encode(csrf); if (prefix.length() != CSRF_STRING_SIZE) { throw new AssertionError("unexpected CSRF token length: " + prefix.length()); } if (request.sessionStore != null) { request.sessionStore.set(prefix); } if (request.state == null) { return prefix; } else { String combined = prefix + request.state; if (combined.length() > Request.MAX_STATE_SIZE) { throw new AssertionError("unexpected combined state length: " + combined.length()); } return combined; } } private static String verifyAndStripCsrfToken(String state, DbxSessionStore sessionStore) throws CsrfException, BadStateException { String expected = sessionStore.get(); if (expected == null) { throw new BadStateException("No CSRF Token loaded from session store."); } if (expected.length() < CSRF_STRING_SIZE) { throw new BadStateException("Token retrieved from session store is too small: " + expected); } if (state.length() < CSRF_STRING_SIZE) { throw new CsrfException("Token too small: " + state); } String actual = state.substring(0, CSRF_STRING_SIZE); if (!StringUtil.secureStringEquals(expected, actual)) { throw new CsrfException("expecting " + jq(expected) + ", got " + jq(actual)); } String stripped = state.substring(CSRF_STRING_SIZE, state.length()); sessionStore.clear(); return stripped.isEmpty() ? null : stripped; } private static /*@Nullable*/String getParam(Map params, String name) throws BadRequestException { String[] v = params.get(name); if (v == null) { return null; } else if (v.length == 0) { throw new IllegalArgumentException("Parameter \"" + name + "\" missing value."); } else if (v.length == 1) { return v[0]; } else { throw new BadRequestException("multiple occurrences of \"" + name + "\" parameter"); } } /** * The base class for authorization redirect errors. You should catch each subclass * individually. */ public static abstract class Exception extends java.lang.Exception { private static final long serialVersionUID = 0L; public Exception(String message) { super(message); } } /** * Thrown when the parameters passed to your redirect URI are not well-formed. * *

* IMPORTANT: The exception's message must not be shown the the user, but may be logged. *

* *

* The recommended action is to show an HTTP 400 error page. *

*/ public static final class BadRequestException extends Exception { private static final long serialVersionUID = 0L; public BadRequestException(String message) { super(message); } } /** * Thrown if all the parameters to your redirect URI are well-formed, but there's no CSRF token * in the session. This probably means that the user's session expired and they must restart * the OAuth 2 process. * *

* IMPORTANT: The exception's message must not be shown the the user, but may be logged. *

* *

* The recommended action is to redirect the user's browser to try the approval process again. *

*/ public static final class BadStateException extends Exception { private static final long serialVersionUID = 0L; public BadStateException(String message) { super(message); } } /** * Thrown if the given 'state' parameter doesn't contain the expected CSRF token. This request * should be blocked to prevent CSRF attacks. * *

* IMPORTANT: The exception's message must not be shown the the user, but may be logged. *

* *

* The recommended action is to show an HTTP 403 error page. *

*/ public static final class CsrfException extends Exception { private static final long serialVersionUID = 0L; public CsrfException(String message) { super(message); } } /** * Thrown when Dropbox tells us that the user chose not to grant your app access to their * Dropbox account (i.e. the user clicked the "Deny" button). * *

* IMPORTANT: The exception's message must not be shown the the user, but may be logged. *

*/ public static final class NotApprovedException extends Exception { private static final long serialVersionUID = 0L; public NotApprovedException(String message) { super(message); } } /** * Thrown when Dropbox tells us that some other error occurred in the authorization process. * *

* IMPORTANT: The exception's message should not be shown the the user, but should be logged. *

*/ public static final class ProviderException extends Exception { private static final long serialVersionUID = 0L; public ProviderException(String message) { super(message); } } /** * Returns a new request builder with default values (e.g. no redirect). * * @return new request builder with default values */ public static Request.Builder newRequestBuilder() { return Request.newBuilder(); } /** * OAuth web-based authorization flow request. * * Used by {@link #authorize} for initiating OAuth web-based authorization flows. */ public static final class Request { private static final Charset UTF8 = Charset.forName("UTF-8"); private static final int MAX_STATE_SIZE = 500; private final String redirectUri; private final String state; private final String requireRole; private final Boolean forceReapprove; private final Boolean disableSignup; private final DbxSessionStore sessionStore; private Request(String redirectUri, String state, String requireRole, Boolean forceReapprove, Boolean disableSignup, DbxSessionStore sessionStore) { this.redirectUri = redirectUri; this.state = state; this.requireRole = requireRole; this.forceReapprove = forceReapprove; this.disableSignup = disableSignup; this.sessionStore = sessionStore; } /** * Returns a copy of this request. * * @return copy of this request */ public Builder copy() { return new Builder(redirectUri, state, requireRole, forceReapprove, disableSignup, sessionStore); } /** * Returns a new request builder with default values (e.g. no redirect). * * @return new request builder with default values */ public static Builder newBuilder() { return new Builder(); } /** * Builder for OAuth2 requests. Use this builder to configure the OAuth authorization flow. */ public static final class Builder { private String redirectUri; private String state; private String requireRole; private Boolean forceReapprove; private Boolean disableSignup; private DbxSessionStore sessionStore; private Builder() { this(null, null, null, null, null, null); } private Builder(String redirectUri, String state, String requireRole, Boolean forceReapprove, Boolean disableSignup, DbxSessionStore sessionStore) { this.redirectUri = redirectUri; this.state = state; this.requireRole = requireRole; this.forceReapprove = forceReapprove; this.disableSignup = disableSignup; this.sessionStore = sessionStore; } /** * Do not redirect the user after authorization has completed (default). * *

After a user authorizes the app using the authorization URL, a code will be * displayed that they must copy and paste into your app. If you want users to be * redirected after authorization back to your app, use {@link #withRedirectUri} * instead. Websites should always provide a redirect URI. * * @return this builder */ public Builder withNoRedirect() { this.redirectUri = null; this.sessionStore = null; return this; } /** * Where to redirect the user after authorization has completed. * *

This must be the exact URI registered in the App Console; * even {@code "localhost"} must be listed if it is used for testing. All redirect URIs must be * HTTPS except for localhost URIs. If the redirect URI is omitted, the code will be * presented directly to the user and they will be invited to enter the information in * your app. * *

The given session store will be used for storing the Cross-Site Request Forgery * (CSRF) nonce generated during the authorization flow. To prevent CSRF attacks, {@link * DbxWebAuth} appends a nonce to each authorization request. When the authorization * flow is complete, the returned nonce is compared with the one in the store to ensure * the response is valid. A session store must be specified if a redirect URI is * set. * * @param redirectUri URI to redirect authorization response, never {@code null}. * @param sessionStore Session store to use for storing CSRF nonces across requests, never {@code null}. * * @return this builder * * @throws NullPointerException if either redirectUri or sessionStore is {@code null} */ public Builder withRedirectUri(String redirectUri, DbxSessionStore sessionStore) { if (redirectUri == null) throw new NullPointerException("redirectUri"); if (sessionStore == null) throw new NullPointerException("sessionStore"); this.redirectUri = redirectUri; this.sessionStore = sessionStore; return this; } /** * Up to 476 bytes of arbitrary data that will be passed back to your redirect URI. * *

Note that {@link DbxWebAuth} will always automatically append a nonce to the * state to protect against cross-site request forgery. This is true even if no state is * provided. * *

State should only be provided if a redirect URI is provided as well, otherwise * {@link #build} will throw an {@link IllegalStateException}. * * @param state additional state to pass back to the redirect URI, or {@code null} to * pass back no additional state. * * @return this builder * * @throws IllegalArgumentException if state is greater than 476 bytes */ public Builder withState(String state) { if (state != null && (state.getBytes(UTF8).length + CSRF_STRING_SIZE) > MAX_STATE_SIZE) { throw new IllegalArgumentException("UTF-8 encoded state cannot be greater than " + (MAX_STATE_SIZE - CSRF_STRING_SIZE) + " bytes."); } this.state = state; return this; } /** * Request the user authorize with the particular type of Dropbox account. * * If specified, the user will be asked to authorize with a particular type of Dropbox * account (e.g. a team account or personal account). * * @param requireRole which role should authorize this app, or {@code null} for any * role. * * @return this builder * * @see DbxWebAuth#ROLE_WORK * @see DbxWebAuth#ROLE_PERSONAL */ public Builder withRequireRole(String requireRole) { this.requireRole = requireRole; return this; } /** * Whether or not to force the user to approve the app again if they've already done so. * *

If {@code false} (default), a user who has already approved the application may * be automatically redirected to the URI specified by {@link #withRedirectUri}. If * {@code true}, the user will not be automatically redirected and will have to approve * the app again. * * @return this builder * * @param forceReapprove whether to force a user to re-approve this app, or {@code null} * for default behavior */ public Builder withForceReapprove(Boolean forceReapprove) { this.forceReapprove = forceReapprove; return this; } /** * Whether or not to allow non-users to sign up for a Dropbox account via the authorization page. * *

When {@code true} (default is {@code false}) users will not be able to sign up * for a Dropbox account via the authorization page. Instead, the authorization page * will show a link to install Dropbox (typically through a mobile app store). This is * only intended for use when necessary for compliance with App Store policies. * * @param disableSignup whether or not to allow users to sign up in the authorization * flow, or {@code null} for default behavior * * @return this builder */ public Builder withDisableSignup(Boolean disableSignup) { this.disableSignup = disableSignup; return this; } /** * Returns a new OAuth {@link Request} that can be used in * {@link DbxWebAuth#DbxWebAuth(DbxRequestConfig,DbxAppInfo)} to authorize a user. * * @return new OAuth {@link Request} configuration. * * @throws IllegalStateException if {@link #withState} was called with a non-{@code * null} value, but no redirect URI was specified. */ public Request build() { if (redirectUri == null && state != null) { throw new IllegalStateException("Cannot specify a state without a redirect URI."); } return new Request(redirectUri, state, requireRole, forceReapprove, disableSignup, sessionStore); } } } }





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