我已仔细阅读 Google Contacts API 文档，但无法正确获取 PUT 请求（即更新）。我正在使用 Ruby on Rails 3.2 和 OAuth gem (v0.4.5)。我使用 Omniauth 获取令牌，范围定义为“ https://www.google.com/m8/feeds ”
让我演示一下：
ruby-1.9.2-p290 :001 > @access_token.get("https://www.google.com/m8/feeds/contacts/default/full/c1f86b48b52548c", {"GData-Version" => "3.0"})
=> #<Net::HTTPOK 200 OK readbody=true>
如您所见，GET 请求运行良好，因此我的 OAuth 访问令牌应该没问题。DELETE 请求也有效：
ruby-1.9.2-p290 :002 > @access_token.delete('https://www.google.com/m8/feeds/contacts/default/full/c1f86b48b52548c', { 'GData-Version' => '3.0', 'If-Match' => '"RH46fTVSLyt7I2A9Wx9VFkgMQAU."' })
=> #<Net::HTTPOK 200 OK readbody=true>
到目前为止，一切都很好。在这里，我按照 Google 文档 [1] 中的说明在请求标头中提供了联系人条目的 Etag。所以它不应该造成任何麻烦。
根据 OAuth gem 文档 [2]，PUT 请求的语法应如下所示：
- (Object) put(path, body = '', headers = {})
以及文档中的一个示例：
@token.put('/people/123', @person.to_xml, { 'Accept' => 'application/xml', 'Content-Type' => 'application/xml' })
据我了解，我应该发送一个简单的 XML 字符串作为 PUT 请求的正文。所以让我们先获取一些示例数据：
ruby-1.9.2-p290 :003 > xmldata = @access_token.get("https://www.google.com/m8/feeds/contacts/default/full/5f74bf0d5c621a", {"GData-Version" => "3.0"}).body
=> "<?xml version='1.0' encoding='UTF-8'?>
<entry xmlns='http://www.w3.org/2005/Atom' xmlns:gContact='http://schemas.google.com/contact/2008' xmlns:batch='http://schemas.google.com/gdata/batch' xmlns:gd='http://schemas.google.com/g/2005' gd:etag='"R3w4fzVSLit7I2A9WhRaGEQCQgc."'>
<id>http://www.google.com/m8/feeds/contacts/my.email%40address.com/base/5f74bf0d5c621a</id>
<updated>2012-02-22T08:15:36.237Z</updated>
<app:edited xmlns:app='http://www.w3.org/2007/app'>2012-02-22T08:15:36.237Z</app:edited>
<category scheme='http://schemas.google.com/g/2005#kind' term='http://schemas.google.com/contact/2008#contact'/>
<title>Joe Average</title>
<link rel='http://schemas.google.com/contacts/2008/rel#photo' type='image/*' href='https://www.google.com/m8/feeds/photos/media/my.email%40address.com/5f74bf0d5c621a?v=3.0'/>
<link rel='self' type='application/atom+xml' href='https://www.google.com/m8/feeds/contacts/my.email%40address.com/full/5f74bf0d5c621a?v=3.0'/>
<link rel='edit' type='application/atom+xml' href='https://www.google.com/m8/feeds/contacts/my.email%40address.com/full/5f74bf0d5c621a?v=3.0'/>
<gd:name>
<gd:fullName>Joe Average</gd:fullName>
<gd:givenName>Joe</gd:givenName>
<gd:familyName>Average</gd:familyName>
</gd:name>
<gd:email rel='http://schemas.google.com/g/2005#other' address='joe.average@isp.net' primary='true'/>
</entry>"
...并尝试将其更新回 Google：
ruby-1.9.2-p290 :004 > @access_token.put("https://www.google.com/m8/feeds/contacts/default/full/5f74bf0d5c621a", xmldata, {"GData-Version" => "3.0", 'If-Match' => '"R3w4fzVSLit7I2A9WhRaGEQCQgc."'})
=> #<Net::HTTPUnauthorized 401 Unknown authorization header readbody=true>
所以这行不通。让我们尝试对 XML 进行一些精简，使其看起来像文档 [1] 中的样子：
xmldata = "<entry gd:etag='"R3w4fzVSLit7I2A9WhRaGEQCQgc."'>
<id>http://www.google.com/m8/feeds/contacts/my.email%40address.com/base/5f74bf0d5c621a</id>
<updated>2012-02-22T08:15:36.237Z</updated>
<category scheme='http://schemas.google.com/g/2005#kind' term='http://schemas.google.com/contact/2008#contact'/>
<link rel='http://schemas.google.com/contacts/2008/rel#photo' type='image/*' href='https://www.google.com/m8/feeds/photos/media/my.email%40address.com/5f74bf0d5c621a?v=3.0'/>
<link rel='self' type='application/atom+xml' href='https://www.google.com/m8/feeds/contacts/my.email%40address.com/full/5f74bf0d5c621a?v=3.0'/>
<link rel='edit' type='application/atom+xml' href='https://www.google.com/m8/feeds/contacts/my.email%40address.com/full/5f74bf0d5c621a?v=3.0'/>
<gd:name>
<gd:fullName>Joe Average</gd:fullName>
<gd:givenName>Joe</gd:givenName>
<gd:familyName>Average</gd:familyName>
</gd:name>
<gd:email rel='http://schemas.google.com/g/2005#other' address='joe.average@isp.net' primary='true'/>
</entry>"
但是没有运气，和以前完全一样的错误。
这就是我现在完全陷入困境的地方。我将不胜感激任何正确方向的提示。
[1] https://developers.google.com/google-apps/contacts/v3/#updating_contacts