如何解决Nexus不为现有数据库从添加的存储库中查找工件的问题？

Question

当我为我的项目在pom.xml中添加对eXist-db工件的依赖时，一切都如我所期望的那样正常工作。下面是添加到pom中的片段：

<dependencies>
<dependency>
  <groupId>org.exist-db</groupId>
  <artifactId>exist-core</artifactId>
  <version>3.2.0</version>
</dependency>
</dependencies>

<repositories>
<repository>
  <id>exist</id>
  <url>https://raw.github.com/eXist-db/mvn-repo/master/</url>
</repository>
</repositories>

但是，当我想使用Nexus (nexus-2.14.4-03)导入依赖项时，我很难让它正常工作。在我的项目的pom.xml中，我删除了存储库元素，使其通过Nexus存储库工作。

在Nexus中，我为eXist工件添加了新的代理存储库。而不是将存储库添加到公共存储库组中。此外，在maven的settings.xml中，我添加了如下镜像代码：

<mirror>
    <id>nexus</id>
    <url>http://localhost:8081/nexus/content/groups/public/</url>
    <mirrorOf>central</mirrorOf>
    <name>Nexus Repository.</name>
</mirror>

Nexus存储库似乎可以工作。我可以从Nexus浏览它，将它看作Eclipse中的全局存储库，并在浏览器中检查它，其中包含工件列表，但eXist-db除外。

回到问题上。在Nexus中的eXist代理存储库设置中，当我将https://raw.github.com/eXist-db/mvn-repo/master/作为远程存储位置时，我有Remote Automatically Blocked and Unavailable消息。顺便说一下，该链接被重定向到https://raw.githubusercontent.com/eXist-db/mvn-repo/master/，并且从Nexus的wrapper.log文件中我有以下一行：

admin org.sonatype.nexus.proxy.maven.maven2.M2Repository - Remote peer of proxy repository "exist-db" [id=exist-db] threw a org.sonatype.nexus.proxy.RemoteStorageException exception. Connection/transport problems occured while connecting to remote peer of the repository. Auto-blocking this repository to prevent further connection-leaks and known-to-fail outbound connections until administrator fixes the problems, or Nexus detects remote repository as healthy. - Cause(s): Unexpected response code while executing GET method [repositoryId="exist-db", requestPath="/", remoteUrl="https://raw.github.com/eXist-db/mvn-repo/master/"]. Expected: "SUCCESS (200)". Received: 400 : Bad Request

因此，当我试图将这个回购URL放到我要得到的web浏览器中时：400: Invalid request就像预期的那样。

我猜这不是Nexus中代理存储库的正确链接，因为Nexus需要该链接上的工件列表。因此，我将其更改为https://github.com/eXist-db/mvn-repo，Remote Automatically Blocked and Unavailable消息消失了。以下是日志中的行：

INFO  [proxy-3-thread-24] admin org.sonatype.nexus.proxy.storage.remote.httpclient.HttpClientRemoteStorage - Updating remote transport for proxy repository "exist-db" [id=exist-db]...
WARN  [proxy-3-thread-24] admin org.sonatype.nexus.proxy.maven.maven2.M2Repository - Remote peer of proxy repository "exist-db" [id=exist-db] detected as healthy, un-blocking the proxy repository (it was AutoBlocked by Nexus).
INFO  [qtp16973920-132] admin org.sonatype.nexus.configuration.application.DefaultNexusConfiguration - Applying Nexus Configuration due to changes in [Public Repositories] made by admin...
INFO  [ar-4-thread-1] admin org.sonatype.nexus.proxy.maven.routing.internal.ManagerImpl - Unpublished prefix file of "Public Repositories" [id=public] (and is marked for noscrape)
ERROR [qtp16973920-49] admin org.sonatype.nexus.rest.NexusRestletResource - java.lang.StringIndexOutOfBoundsException: String index out of range: -10
java.lang.AbstractStringBuilder.substring(AbstractStringBuilder.java:935)
at java.lang.StringBuilder.substring(StringBuilder.java:76) ~[na:1.8.0_131]
at org.sonatype.nexus.plugins.rrb.parsers.HtmlRemoteRepositoryParser.getLinkUrl(HtmlRemoteRepositoryParser.java:173) ~[na:na]
...

我试图从Nexus内部更新存储库索引，下面是该操作的日志行：

INFO  [pxpool-1-thread-6] admin org.sonatype.nexus.index.tasks.UpdateIndexTask - Scheduled task (UpdateIndexTask) started :: Updating repository index "exist-db" from path / and below.
INFO  [pxpool-1-thread-6] admin org.sonatype.nexus.index.DefaultIndexerManager - Trying to get remote index for repository "exist-db" [id=exist-db]
INFO  [pxpool-1-thread-6] admin org.sonatype.nexus.index.DefaultIndexerManager - Cannot fetch remote index for repository "exist-db" [id=exist-db] as it does not publish indexes.
INFO  [pxpool-1-thread-6] admin org.sonatype.nexus.index.NexusScanningListener - Scanning of repositoryID="exist-db" started.
INFO  [pxpool-1-thread-6] admin org.sonatype.nexus.index.NexusScanningListener - Scanning of repositoryID="exist-db" finished: scanned=0, added=0, updated=0, removed=0, scanningDuration=0:00:00.328
INFO  [pxpool-1-thread-6] admin org.sonatype.nexus.index.DefaultIndexerManager - Publishing index for repository exist-db
INFO  [pxpool-1-thread-6] admin org.sonatype.nexus.index.tasks.UpdateIndexTask - Scheduled task (UpdateIndexTask) finished :: Updating repository index "exist-db" from path / and below. (started 2017-06-29T15:53:28+02:00, runtime 0:00:01.375)

最后，在我的exist-db代理存储库的路由选项卡下的Nexus中，有：

Publishing:
Status: Not published.
Message: Discovery in progress or unable to discover remote content (see discovery status).

Discovery:
Status: Unsuccessful.
Message: No scraper was able to scrape remote (or remote prevents scraping).

我在项目的pom.xml上获得了Eclipse中的错误消息，声明：

Missing artifact org.exist-db:exist-core:jar:3.2.0

有人能告诉我我在这里错过了什么吗？谢谢。

Answer 1

不幸的是，原始的GitHub回购只适用于mvn命令行工具。它不能作为Nexus代理的来源。

然而，我的公司维护一个公开的Nexus，其中包含最新的eXist工件：http://repo.evolvedbinary.com/content/repositories/exist-db/。

虽然上面的URL仍然有效，但我们现在已经更新到Nexus 3，它更喜欢现在应该从：http://repo.evolvedbinary.com/repository/exist-db/访问存储库的更新的URL样式。