HTTPCaller

此参数标识将用于访问服务器的HTTP方法。大多数请求将使用得到method. Requests which upload data will use thePUT,POSTorPATCHmethod. TheHEAD,DELETEandOPTIONSmethods can be useful when accessing a REST API.

This parameter identifies the URL which will be accessed by the transformer. The transformer can access http and https URLs. The URL can be entered directly in the transformer, or be built up from attribute values.

This parameter identifies the type of data that will be uploaded. The transformer can upload a file, a string value, or a multi-part combination of file and string values.

Upload data may be entered using this parameter. The data may be entered directly into the transformer or constructed from attribute values.

上传文件时，此参数提供文件路径。路径可以直接输入到变压器中或从属性值设置。

When uploading a string value or a file, this parameter provides the data content type. The value of this parameter will be sent in the Content-Type request header. The drop-down list contains a number of commonly-used content type values. If a different value is required, it can be typed into the text field, or derived from an attribute value.

This table is used to construct multipart uploads. Each part in a multipart upload must have a name, which is given in the first column. The second column identifies the type of part – either a file or a string value. The third column provides the data and MIME type for the part.

This parameter allows users to set the destination for the HTTP response body. The body may be saved to an attribute, or to a file.

Note:如果您正在使用HttpCaller下载一个非常大的响应机构，建议将其保存到文件中。这避免在该功能上创建大型属性。

将响应正文保存到属性时，此参数名称将使用的属性。默认属性名称是_response_body。执行HTTP HEAD请求时，此属性将为空。

此参数用于指示目标属性的字符编码。默认情况下，属性编码将自动从HTTP响应标头自动确定。或者，可以从列表中选择特定编码。下载二进制数据时，应将参数设置为BinaryorAuto Detect from HTTP Headers。

This parameter controls the manner in which the transformer will save response bodies to files. There are two modes:

• No：响应主体将保存到指定的文件中Output Filename参数。
• Yes：将为每个功能创建一个新文件，并保存在指定的文件夹中Output Folder参数。

当。。。的时候Create a New File Per Feature参数设置为No, the transformer will save HTTP response bodies to the file specified in this parameter. The file may be selected directly, or set from an attribute. Note that if the file is selected directly, the file will be overwritten by each feature passing through the transformer. If more than one feature is passing through the transformer, it is recommended that the file path be set to a unique attribute value, or that the transformer be configured to create a new file for each feature.

当。。。的时候Create a New File Per Feature参数设置为Yes, the transformer will create a new file for each feature passing through the transformer. The files will be saved in the folder specified in this parameter.

IfCreate a New File Per Feature是Yes, this parameter specifies the file type extension for the new file names. Select from a list of common file types, type in manually, or automatically set based on the Content-Type header in the HTTP response.

After the response body has been saved to a file, the attribute named in this parameter will be set to the file path.

此参数是可选的。If it is set to a list attribute name, then HTTP headers returned by the server will be stored in the list attribute. The headers will be split into names and values. For example:

“_headers{0}.name' has value `X-XSS-Protection'

“_headers{0}.value' has value `1; mode=block'

“_headers{1}.name' has value `Date'

“_headers{1}.value' has value `Wed, 25 May 2011 17:20:20 GMT'

“_headers{2}.name' has value `Transfer-Encoding'

`_headers {2} .value'有价值`chunded'

“_headers{3}.name' has value `Content-Type'

“_headers{3}.value' has value `text/html; charset=ISO-8859-1'

“_headers{4}.name' has value `Cache-Control'

“_headers{4}.value' has value `private, max-age=0'

此参数是可选的。如果它设置为属性名称，则服务器返回的HTTP响应代码将存储在该属性中。

此参数是可选的。If an error occurs, the feature will be output through theoutput port, and the attribute named in this parameter will contain a brief error message.

If this parameter is set toYes, any saved cookies that correspond to the URL being accessed will be sent with the request. In addition, any cookies contained in the response will be saved for use with subsequent HTTP requests.

Saved cookies will persist for the duration of the translation – they cannot be used in subsequent translations.

当Web服务保存“会话”时，保存cookie很有用。然后可以使用以下操作序列：

1. An HTTPCaller transformer is used to log in to the web service and a session cookie is saved.
2. A second HTTPCaller transformer is used to access the web service, utilizing the saved session cookie.
3. A third HTTPCaller is used to log out of the web service, which invalidates the saved cookie.

If this parameter is set toYes, the transformer will follow any URL redirects it encounters, making a second request to a new location.

If this parameter is set toYes，变压器将验证SSL证书。这是在两个阶段完成的：

1. Ensure that the certificate is for the host we are trying to connect to.
2. Ensure that the certificate is valid.

This parameter can be used to set a timeout on HTTP connection requests. If a connection to the server cannot be created within the given number of seconds, the request will fail, and the feature will be output through the港口。The default connection timeout is 60 seconds. If 0 is entered, there will be no timeout, and the transformer will wait indefinitely for a successful connection.

This parameter can be used to set a timeout on HTTP transfers. If data stops being transferred for more than the given number of seconds, the request will fail, and the feature will be output through the港口。默认传输超时为90秒。如果输入0，则不会存在超时，并且变压器将无限期地等待数据以恢复被传输。

变换器以两种方式支持用户身份验证：命名连接和用户名/密码身份验证。

命名连接选项允许选择存储的命名连接，这将使用相应的Web服务验证用户。要添加一个新的命名连接，请从命名的Connection下拉菜单中选择“添加连接...”。命名连接选项允许使用支持的Web服务进行OAuth2身份验证。

When authenticating with a username and password, the basic, digest and NTLM access authentication methods are supported:

• 基础(HTTP Basic authentication): This is the default choice, and the only method in widespread use and supported virtually everywhere. This sends the username and password over the network in plain text, easily captured by others.
• 消化(HTTP Digest authentication): Digest authentication is more secure over public networks than the Basic method.
• NTLM(HTTP NTLM authentication): NTLM is a proprietary protocol invented and used by Microsoft. It uses a challenge-response and hash concept similar to Digest to prevent the password from being eavesdropped.

Note:注意，尽管HTTP基本访问认证是旨在允许客户端向服务器提供凭证的机制，但是假设它们之间的连接是可信和安全的，请注意通过客户端传递给服务器的任何凭据可以轻松拦截不安全的连接。