Package org.springframework.cloud.stream.binder.kafka

Class BinderHeaderMapper

  • All Implemented Interfaces:
    org.springframework.kafka.support.KafkaHeaderMapper
    public class BinderHeaderMapper
extends org.springframework.kafka.support.AbstractKafkaHeaderMapper
    Custom header mapper for Apache Kafka. This is identical to the DefaultKafkaHeaderMapper from spring Kafka. This is provided for addressing some interoperability issues between Spring Cloud Stream 3.0.x and 2.x apps, where mime types passed as regular MimeType in the header are not de-serialized properly. It also suppresses certain internal headers that should never be propagated on output. Most headers in KafkaHeaders are not mapped onto outbound messages. The exceptions are correlation and reply headers for request/reply messaging. Header types are added to a special header JSON_TYPES.
    Since:
    3.0.0
    Author:
    Gary Russell, Artem Bilan, Soby Chacko

    • Nested Class Summary

      Nested Classes 
      Modifier and Type Class Description
      static class  BinderHeaderMapper.NonTrustedHeaderType
      Represents a header that could not be decoded due to an untrusted type.

      • Nested classes/interfaces inherited from class org.springframework.kafka.support.AbstractKafkaHeaderMapper

        org.springframework.kafka.support.AbstractKafkaHeaderMapper.HeaderMatcher, org.springframework.kafka.support.AbstractKafkaHeaderMapper.NeverMatchHeaderMatcher, org.springframework.kafka.support.AbstractKafkaHeaderMapper.SimplePatternBasedHeaderMatcher

    • Field Summary

      Fields 
      Modifier and Type Field Description
      static String JSON_TYPES
      Header name for java types of other headers.

      • Fields inherited from class org.springframework.kafka.support.AbstractKafkaHeaderMapper

        logger

    • Constructor Summary

      Constructors 
      Constructor Description
      BinderHeaderMapper()
      Construct an instance with the default object mapper and default header patterns for outbound headers; all inbound headers are mapped.
      BinderHeaderMapper​(com.fasterxml.jackson.databind.ObjectMapper objectMapper)
      Construct an instance with the provided object mapper and default header patterns for outbound headers; all inbound headers are mapped.
      BinderHeaderMapper​(com.fasterxml.jackson.databind.ObjectMapper objectMapper, String... patterns)
      Construct an instance with the provided object mapper and the provided header patterns for outbound headers; all inbound headers are mapped.
      BinderHeaderMapper​(String... patterns)
      Construct an instance with a default object mapper and the provided header patterns for outbound headers; all inbound headers are mapped.

    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      static String[] addNeverHeaderPatterns​(List<String> patterns)
      Add patterns for headers that should never be mapped.
      void addToStringClasses​(String... classNames)
      Add class names that the outbound mapper should perform toString() operations on before mapping.
      void addTrustedPackages​(String... packagesToTrust)
      Add packages to the trusted packages list (default java.util, java.lang) used when constructing objects from JSON.
      void fromHeaders​(org.springframework.messaging.MessageHeaders headers, org.apache.kafka.common.header.Headers target)  
      protected com.fasterxml.jackson.databind.ObjectMapper getObjectMapper()
      Return the object mapper.
      protected Set<String> getToStringClasses()
      Provide direct access to the toString() classes by subclasses.
      protected Set<String> getTrustedPackages()
      Provide direct access to the trusted packages set for subclasses.
      protected boolean isEncodeStrings()  
      static void removeNeverHeaders​(org.apache.kafka.common.header.Headers headers)
      Remove never headers.
      void setEncodeStrings​(boolean encodeStrings)
      Set to true to encode String-valued headers as JSON ("..."), by default just the raw String value is converted to a byte array using the configured charset.
      void toHeaders​(org.apache.kafka.common.header.Headers source, Map<String,​Object> headers)  
      protected boolean trusted​(String requestedType)  

      • Methods inherited from class org.springframework.kafka.support.AbstractKafkaHeaderMapper

        addMatchers, addRawMappedHeader, getCharset, headerValueToAddIn, headerValueToAddOut, matches, matches, matchesForInbound, setCharset, setMapAllStringsOut, setRawMappedHeaders

    • Constructor Detail

      • BinderHeaderMapper

        public BinderHeaderMapper()
        Construct an instance with the default object mapper and default header patterns for outbound headers; all inbound headers are mapped. The default pattern list is "!id", "!timestamp" and "*". In addition, most of the headers in KafkaHeaders are never mapped as headers since they represent data in consumer/producer records.
        See Also:
        BinderHeaderMapper(ObjectMapper)

      • BinderHeaderMapper

        public BinderHeaderMapper​(com.fasterxml.jackson.databind.ObjectMapper objectMapper)
        Construct an instance with the provided object mapper and default header patterns for outbound headers; all inbound headers are mapped. The patterns are applied in order, stopping on the first match (positive or negative). Patterns are negated by preceding them with "!". The default pattern list is "!id", "!timestamp" and "*". In addition, most of the headers in KafkaHeaders are never mapped as headers since they represent data in consumer/producer records.
        Parameters:
        objectMapper - the object mapper.
        See Also:
        PatternMatchUtils.simpleMatch(String, String)

      • BinderHeaderMapper

        public BinderHeaderMapper​(String... patterns)
        Construct an instance with a default object mapper and the provided header patterns for outbound headers; all inbound headers are mapped. The patterns are applied in order, stopping on the first match (positive or negative). Patterns are negated by preceding them with "!". The patterns will replace the default patterns; you generally should not map the "id" and "timestamp" headers. Note: most of the headers in KafkaHeaders are ever mapped as headers since they represent data in consumer/producer records.
        Parameters:
        patterns - the patterns.
        See Also:
        PatternMatchUtils.simpleMatch(String, String)

      • BinderHeaderMapper

        public BinderHeaderMapper​(com.fasterxml.jackson.databind.ObjectMapper objectMapper,
                          String... patterns)
        Construct an instance with the provided object mapper and the provided header patterns for outbound headers; all inbound headers are mapped. The patterns are applied in order, stopping on the first match (positive or negative). Patterns are negated by preceding them with "!". The patterns will replace the default patterns; you generally should not map the "id" and "timestamp" headers. Note: most of the headers in KafkaHeaders are never mapped as headers since they represent data in consumer/producer records.
        Parameters:
        objectMapper - the object mapper.
        patterns - the patterns.
        See Also:
        PatternMatchUtils.simpleMatch(String, String)

    • Method Detail

      • getObjectMapper

        protected com.fasterxml.jackson.databind.ObjectMapper getObjectMapper()
        Return the object mapper.
        Returns:
        the mapper.

      • getTrustedPackages

        protected Set<String> getTrustedPackages()
        Provide direct access to the trusted packages set for subclasses.
        Returns:
        the trusted packages.
        Since:
        2.2

      • getToStringClasses

        protected Set<String> getToStringClasses()
        Provide direct access to the toString() classes by subclasses.
        Returns:
        the toString() classes.
        Since:
        2.2

      • isEncodeStrings

        protected boolean isEncodeStrings()

      • setEncodeStrings

        public void setEncodeStrings​(boolean encodeStrings)
        Set to true to encode String-valued headers as JSON ("..."), by default just the raw String value is converted to a byte array using the configured charset. Set to true if a consumer of the outbound record is using Spring for Apache Kafka version less than 2.3
        Parameters:
        encodeStrings - true to encode (default false).
        Since:
        2.3

      • addTrustedPackages

        public void addTrustedPackages​(String... packagesToTrust)
        Add packages to the trusted packages list (default java.util, java.lang) used when constructing objects from JSON. If any of the supplied packages is "*", all packages are trusted. If a class for a non-trusted package is encountered, the header is returned to the application with value of type BinderHeaderMapper.NonTrustedHeaderType.
        Parameters:
        packagesToTrust - the packages to trust.

      • addToStringClasses

        public void addToStringClasses​(String... classNames)
        Add class names that the outbound mapper should perform toString() operations on before mapping.
        Parameters:
        classNames - the class names.
        Since:
        2.2

      • fromHeaders

        public void fromHeaders​(org.springframework.messaging.MessageHeaders headers,
                        org.apache.kafka.common.header.Headers target)

      • toHeaders

        public void toHeaders​(org.apache.kafka.common.header.Headers source,
                      Map<String,​Object> headers)

      • trusted

        protected boolean trusted​(String requestedType)

      • addNeverHeaderPatterns

        public static String[] addNeverHeaderPatterns​(List<String> patterns)
        Add patterns for headers that should never be mapped.
        Parameters:
        patterns - the patterns.
        Returns:
        the modified patterns.
        Since:
        3.0.2

      • removeNeverHeaders

        public static void removeNeverHeaders​(org.apache.kafka.common.header.Headers headers)
        Remove never headers.
        Parameters:
        headers - the headers from which to remove the never headers.
        Since:
        3.0.2