azure.core.pipeline.policies.HeadersPolicy.yml

### YamlMime:PythonClass
uid: azure.core.pipeline.policies.HeadersPolicy
name: HeadersPolicy
fullName: azure.core.pipeline.policies.HeadersPolicy
module: azure.core.pipeline.policies
inheritances:
- azure.core.pipeline.policies._base.SansIOHTTPPolicy
summary: 'A simple policy that sends the given headers with the request.


  This will overwrite any headers already defined in the request. Headers can be

  configured up front, where any custom headers will be applied to all outgoing

  operations, and additional headers can also be added dynamically per operation.'
constructor:
  syntax: 'HeadersPolicy(base_headers: Dict[str, str] | None = None, **kwargs: Any)'
  parameters:
  - name: base_headers
    description: Headers to send with the request.
    defaultValue: None
    types:
    - <xref:dict>
examples:
- "Configuring a headers policy.<!--[!code-python[Main](les\\test_example_sansio.py\
  \ )]-->\n\n<!-- literal_block {\"ids\": [], \"classes\": [], \"names\": [], \"dupnames\"\
  : [], \"backrefs\": [], \"source\": \"C:\\\\hostedtoolcache\\\\windows\\\\Python\\\
  \\3.11.9\\\\x64\\\\Lib\\\\site-packages\\\\py2docfx\\\\dist_temp\\\\35\\\\azure-core-1.30.2\\\
  \\samples\\\\test_example_sansio.py\", \"xml:space\": \"preserve\", \"force\": false,\
  \ \"language\": \"python\", \"highlight_args\": {\"linenostart\": 1}, \"linenos\"\
  : false} -->\n\n````python\n\n   from azure.core.pipeline.policies import HeadersPolicy\n\
  \n   headers_policy = HeadersPolicy()\n   headers_policy.add_header(\"CustomValue\"\
  , \"Foo\")\n\n   # Or headers can be added per operation. These headers will supplement\
  \ existing headers\n   # or those defined in the config headers policy. They will\
  \ also overwrite existing\n   # identical headers.\n   policies.append(headers_policy)\n\
  \   client: PipelineClient[HttpRequest, HttpResponse] = PipelineClient(base_url=url,\
  \ policies=policies)\n   request = HttpRequest(\"GET\", url)\n   pipeline_response\
  \ = client._pipeline.run(request, headers={\"CustomValue\": \"Bar\"})\n\n   ````\n"
methods:
- uid: azure.core.pipeline.policies.HeadersPolicy.add_header
  name: add_header
  summary: Add a header to the configuration to be applied to all requests.
  signature: 'add_header(key: str, value: str) -> None'
  parameters:
  - name: key
    description: The header.
    isRequired: true
    types:
    - <xref:str>
  - name: value
    description: The header's value.
    isRequired: true
    types:
    - <xref:str>
- uid: azure.core.pipeline.policies.HeadersPolicy.on_exception
  name: on_exception
  summary: 'Is executed if an exception is raised while executing the next policy.


    This method is executed inside the exception handler.'
  signature: 'on_exception(request: PipelineRequest[HTTPRequestType]) -> None'
  parameters:
  - name: request
    description: The Pipeline request object
    isRequired: true
    types:
    - <xref:azure.core.pipeline.PipelineRequest>
- uid: azure.core.pipeline.policies.HeadersPolicy.on_request
  name: on_request
  summary: Updates with the given headers before sending the request to the next policy.
  signature: 'on_request(request: PipelineRequest[HttpRequest | HttpRequest]) -> None'
  parameters:
  - name: request
    description: The PipelineRequest object
    isRequired: true
    types:
    - <xref:azure.core.pipeline.PipelineRequest>
- uid: azure.core.pipeline.policies.HeadersPolicy.on_response
  name: on_response
  summary: Is executed after the request comes back from the policy.
  signature: 'on_response(request: PipelineRequest[HTTPRequestType], response: PipelineResponse[HTTPRequestType,
    HTTPResponseType]) -> None | Awaitable[None]'
  parameters:
  - name: request
    description: Request to be modified after returning from the policy.
    isRequired: true
    types:
    - <xref:azure.core.pipeline.PipelineRequest>
  - name: response
    description: Pipeline response object
    isRequired: true
    types:
    - <xref:azure.core.pipeline.PipelineResponse>
attributes:
- uid: azure.core.pipeline.policies.HeadersPolicy.headers
  name: headers
  summary: The current headers collection.
  return:
    description: The current headers collection.
    types:
    - <xref:dict>[<xref:str>, <xref:str>]