问题描述
在App Engine应用程序上，该应用程序部署在激活了Java 8的标准环境中，如果同时使用Objectify 6.0和appengine-web.xml文件中的标记<url-stream-handler>urlfetch</url-stream-handler>，则会出现以下异常.
On an App Engine application, deployed on standard environment with java 8 activated, I get the exception below if I use both Objectify 6.0 AND the tag <url-stream-handler>urlfetch</url-stream-handler> in the appengine-web.xml file.
com.google.cloud.datastore.DatastoreException: Request is missing required authentication credential. Expected OAuth 2 access token, login cookie or other valid authentication credential. See https://developers.google.com/identity/sign-in/web/devconsole-project.
有什么主意我可以绕开它吗?
Any idea how I can bypass that?
如果我删除urlfetch标签(并激活账单)或将Objectify降级到v5，一切都会恢复正常.
Things get back to normal if I remove the urlfetch tag (and activate the billing) or if I downgrade Objectify to v5.
推荐答案
我怀疑您遇到的是Java 7和Java 8 Standard Environments之间的差异之一.避免使用urlfetch路径有很多好处，因为发出HTTP( S)请求注释(例如HTTP/2).特别是，使用urlfetch(请参见该页面)无法访问元数据服务器，该元数据服务器在App Engine上运行时会对Google Cloud SDK进行自动身份验证.
I suspect what you're running into is one of the differences between the Java 7 and the Java 8 Standard Environments. There are substantial benefits to avoiding the urlfetch path, as Issuing HTTP(S) Requests notes (e.g. HTTP/2). In particular, the metadata server, which does automatic authentication for the Google Cloud SDKs when running on App Engine, isn't reachable using urlfetch (see that page).
我认为，如果您愿意，最好的选择就是启用计费功能.在文档页面上:
I think your best option here is probably to enable billing, if you're comfortable with that. From the docs page:
如果您仍然想尝试urlfetch，我认为您可以通过手动提供凭据(例如，将其捆绑在您的应用程序中)来解决所遇到的错误，但这不会那么安全或表演者.
If you'd still like to give urlfetch a try, I think the error you're encountering can be fixed by manually supplying credentials (e.g. bundling them in your app), but that won't be as secure or performant.
这篇关于得到"DatastoreException:请求缺少必需的认证凭证".如果使用Objectify 6.0和< url-stream-handler>同时的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！