.. _program_listing_file_include_opentelemetry_context_propagation_text_map_propagator.h:

Program Listing for File text_map_propagator.h
==============================================

|exhale_lsh| :ref:`Return to documentation for file <file_include_opentelemetry_context_propagation_text_map_propagator.h>` (``include/opentelemetry/context/propagation/text_map_propagator.h``)

.. |exhale_lsh| unicode:: U+021B0 .. UPWARDS ARROW WITH TIP LEFTWARDS

.. code-block:: cpp

   // Copyright The OpenTelemetry Authors
   // SPDX-License-Identifier: Apache-2.0
   
   #pragma once
   
   #include <cstdint>
   #include "opentelemetry/context/context.h"
   #include "opentelemetry/nostd/string_view.h"
   #include "opentelemetry/version.h"
   
   OPENTELEMETRY_BEGIN_NAMESPACE
   namespace context
   {
   namespace propagation
   {
   
   // TextMapCarrier is the storage medium used by TextMapPropagator.
   class TextMapCarrier
   {
   public:
     /*returns the value associated with the passed key.*/
     virtual nostd::string_view Get(nostd::string_view key) const noexcept = 0;
   
     /*stores the key-value pair.*/
     virtual void Set(nostd::string_view key, nostd::string_view value) noexcept = 0;
   };
   
   // The TextMapPropagator class provides an interface that enables extracting and injecting
   // context into carriers that travel in-band across process boundaries. HTTP frameworks and clients
   // can integrate with TextMapPropagator by providing the object containing the
   // headers, and a getter and setter function for the extraction and
   // injection of values, respectively.
   
   class TextMapPropagator
   {
   public:
     // Returns the context that is stored in the carrier with the TextMapCarrier as extractor.
     virtual context::Context Extract(const TextMapCarrier &carrier,
                                      context::Context &context) noexcept = 0;
   
     // Sets the context for carrier with self defined rules.
     virtual void Inject(TextMapCarrier &carrier, const context::Context &context) noexcept = 0;
   };
   }  // namespace propagation
   }  // namespace context
   OPENTELEMETRY_END_NAMESPACE