Expose Jackson2CodecSupport mime types for custom override [SPR-15474]

[spring-projects-issues]

Daniel Lavoie opened SPR-15474 and commented

Some web services offers JSON content without properly typing the content type. For example, a bad api serving json content but setting the content-type to text/plain. The brand new shiny WebClient relies on the Jackson2CodecSupport to decode the stream. Saldy, there is now way to manually define the supported mime types.

The class Jackson2CodecSupport does not offers any means to override the supported mime types.

I can provide a PR to expose an extension mechanism.

Jackson2JsonDecoder

@Override
public boolean canDecode(ResolvableType elementType, MimeType mimeType) {
  JavaType javaType = this.objectMapper.getTypeFactory().constructType(elementType.getType());
  // Skip String: CharSequenceDecoder + "*/*" comes after
  return (!CharSequence.class.isAssignableFrom(elementType.resolve(Object.class)) &&
    this.objectMapper.canDeserialize(javaType) && supportsMimeType(mimeType));
}

Jackson2CodecSupport

  protected static final List<MimeType> JSON_MIME_TYPES = Arrays.asList(
    new MimeType("application", "json", StandardCharsets.UTF_8),
    new MimeType("application", "*+json", StandardCharsets.UTF_8));


  protected boolean supportsMimeType(MimeType mimeType) {
    return (mimeType == null ||
      JSON_MIME_TYPES.stream().anyMatch(m -> m.isCompatibleWith(mimeType)));
  }

---

Affects: 5.0 M1

Referenced from: commits 8231812

[spring-projects-issues]

Rossen Stoyanchev commented

Sure, send a PR.

[spring-projects-issues]

Daniel Lavoie commented

Any guideline you wish that I stick to ? Should this extension mecasnism be appliable to other codecs than jackson's ?

[spring-projects-issues]

Rossen Stoyanchev commented

Let's focus on Jackson to start. For constructor based injection each encoder/decoder has to provide them anyway.