端点“/api-docs”不适用于自定义 GsonHttpMessageConverter

Question

我从 Springfox Swagger 迁移到 Springdoc OpenApi。我在配置中添加了几行关于 springdoc 的内容：

springdoc:
  pathsToMatch: /api/**
  api-docs:
    path: /api-docs
  swagger-ui:
    path: /swagger-ui.html

在配置类MainConfig.kt我有以下代码：

val customGson: Gson = GsonBuilder()
        .registerTypeAdapter(LocalDateTime::class.java, DateSerializer())
        .registerTypeAdapter(ZonedDateTime::class.java, ZonedDateSerializer())
        .addSerializationExclusionStrategy(AnnotationExclusionStrategy())
        .enableComplexMapKeySerialization()
        .setPrettyPrinting()
        .create()

    override fun configureMessageConverters(converters: MutableList<HttpMessageConverter<*>>) {
        converters.add(GsonHttpMessageConverter(customGson))
    }

当我转到 http://localhost:8013/swagger-ui.html（在配置中我有 server.port: 8013）时，页面不会重定向到 swagger-ui/index.html?url=/api-docs&validatorUrl=。但这不是我的主要问题:)。当我转到swagger-ui/index.html?url=/api-docs&validatorUrl= 时，我得到了包含以下信息的页面：

无法呈现此定义 提供的定义未指定有效的版本字段。 请指明有效的 Swagger 或 OpenAPI 版本字段。支持的版本字段是 swagger: "2.0" 和那些与 openapi: 3.0.n 匹配的（例如，openapi: 3.0.0）。

但是当我去 http://localhost:8013/api-docs 我有这个结果：

"{\"openapi\":\"3.0.1\",\"info\":{(...)}}"

我尝试使用默认配置并评论了configureMessageConverters() 方法和\api-docs 的结果现在看起来像普通的 JSON：

// 20191218134933
// http://localhost:8013/api-docs

{
  "openapi": "3.0.1",
  "info": {(...)}
}

我记得当我使用 Springfox 时，序列化出了点问题，我的 customGson 多了一行：.registerTypeAdapter(Json::class.java, JsonSerializer<Json> { src, _, _ -> JsonParser.parseString(src.value()) })

我想知道我应该有特殊的JsonSerializer。调试后，我的第一个想法是导致 io.swagger.v3.oas.models 包中的 OpenApi 类。我添加了这段代码：.registerTypeAdapter(OpenAPI::class.java, JsonSerializer<OpenAPI> { _, _, _ -> JsonParser.parseString("") }) 到 customGson 并没有任何改变......所以，我正在深入挖掘......

在我运行 Swagger 测试之后：

@EnableAutoConfiguration
@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
@AutoConfigureMockMvc
@ExtendWith(SpringExtension::class)
@ActiveProfiles("test")
class SwaggerIntegrationTest(@Autowired private val mockMvc: MockMvc) {
    @Test
    fun `should display Swagger UI page`() {
        val result = mockMvc.perform(MockMvcRequestBuilders.get("/swagger-ui/index.html"))
                .andExpect(status().isOk)
                .andReturn()

        assertTrue(result.response.contentAsString.contains("Swagger UI"))
    }

    @Disabled("Redirect doesn't work. Check it later")
    @Test
    fun `should display Swagger UI page with redirect`() {
        mockMvc.perform(MockMvcRequestBuilders.get("/swagger-ui.html"))
                .andExpect(status().isOk)
                .andExpect(MockMvcResultMatchers.content().contentTypeCompatibleWith(MediaType.TEXT_HTML))
    }

    @Test
    fun `should get api docs`() {
        mockMvc.perform(MockMvcRequestBuilders.get("/api-docs"))
                .andExpect(status().isOk)
                .andExpect(MockMvcResultMatchers.content().contentTypeCompatibleWith(MediaType.APPLICATION_JSON))
                .andExpect(MockMvcResultMatchers.jsonPath("\$.openapi").exists())
    }
}

我在控制台中看到了这个：

MockHttpServletRequest:
      HTTP Method = GET
      Request URI = /api-docs
       Parameters = {}
          Headers = []
             Body = null
    Session Attrs = {}

Handler:
             Type = org.springdoc.api.OpenApiResource
           Method = org.springdoc.api.OpenApiResource#openapiJson(HttpServletRequest, String)

接下来我在OpenApiResource 中检查openapiJson 和...

    @Operation(hidden = true)
    @GetMapping(value = API_DOCS_URL, produces = MediaType.APPLICATION_JSON_VALUE)
    public String openapiJson(HttpServletRequest request, @Value(API_DOCS_URL) String apiDocsUrl)
            throws JsonProcessingException {
        calculateServerUrl(request, apiDocsUrl);
        OpenAPI openAPI = this.getOpenApi();
        return Json.mapper().writeValueAsString(openAPI);
    }

好的，Jackson... 我已通过 @EnableAutoConfiguration(exclude = [(JacksonAutoConfiguration::class)]) 禁用 Jackson，因为我（和我的同事）更喜欢 GSON，但这并不能解释为什么在添加自定义 GsonHttpMessageConverter 后序列化会出错。我不知道我做错了什么。这个openapiJson() 是端点，也许它搞砸了……我不知道。我没有任何想法。你有类似的问题吗？能给点建议或提示吗？

PS。对不起我的英语不好:)。

Answer 1

我在用 Java 编写的项目中遇到了同样的问题，我刚刚通过定义一个过滤器来使用 Gson 格式化我的 springdoc-openapi json 文档来解决这个问题。我想您可以轻松地将这个解决方法移植到 Kotlin。

@Override
public void doFilter(final ServletRequest request, final ServletResponse response, final FilterChain chain)
        throws IOException, ServletException {
    ByteResponseWrapper byteResponseWrapper = new ByteResponseWrapper((HttpServletResponse) response);
    ByteRequestWrapper byteRequestWrapper = new ByteRequestWrapper((HttpServletRequest) request);

    chain.doFilter(byteRequestWrapper, byteResponseWrapper);

    String jsonResponse = new String(byteResponseWrapper.getBytes(), response.getCharacterEncoding());

    response.getOutputStream().write((new com.google.gson.JsonParser().parse(jsonResponse).getAsString())
            .getBytes(response.getCharacterEncoding()));
}

@Override
public void destroy() {

}

static class ByteResponseWrapper extends HttpServletResponseWrapper {

    private PrintWriter writer;
    private ByteOutputStream output;

    public byte[] getBytes() {
        writer.flush();
        return output.getBytes();
    }

    public ByteResponseWrapper(HttpServletResponse response) {
        super(response);
        output = new ByteOutputStream();
        writer = new PrintWriter(output);
    }

    @Override
    public PrintWriter getWriter() {
        return writer;
    }

    @Override
    public ServletOutputStream getOutputStream() {
        return output;
    }
}

static class ByteRequestWrapper extends HttpServletRequestWrapper {

    byte[] requestBytes = null;
    private ByteInputStream byteInputStream;


    public ByteRequestWrapper(HttpServletRequest request) throws IOException {
        super(request);
        ByteArrayOutputStream baos = new ByteArrayOutputStream();

        InputStream inputStream = request.getInputStream();

        byte[] buffer = new byte[4096];
        int read = 0;
        while ((read = inputStream.read(buffer)) != -1) {
            baos.write(buffer, 0, read);
        }

        replaceRequestPayload(baos.toByteArray());
    }

    @Override
    public BufferedReader getReader() {
        return new BufferedReader(new InputStreamReader(getInputStream()));
    }

    @Override
    public ServletInputStream getInputStream() {
        return byteInputStream;
    }

    public void replaceRequestPayload(byte[] newPayload) {
        requestBytes = newPayload;
        byteInputStream = new ByteInputStream(new ByteArrayInputStream(requestBytes));
    }
}

static class ByteOutputStream extends ServletOutputStream {

    private ByteArrayOutputStream bos = new ByteArrayOutputStream();

    @Override
    public void write(int b) {
        bos.write(b);
    }

    public byte[] getBytes() {
        return bos.toByteArray();
    }

    @Override
    public boolean isReady() {
        return false;
    }

    @Override
    public void setWriteListener(WriteListener writeListener) {

    }
}

static class ByteInputStream extends ServletInputStream {

    private InputStream inputStream;

    public ByteInputStream(final InputStream inputStream) {
        this.inputStream = inputStream;
    }

    @Override
    public int read() throws IOException {
        return inputStream.read();
    }

    @Override
    public boolean isFinished() {
        return false;
    }

    @Override
    public boolean isReady() {
        return false;
    }

    @Override
    public void setReadListener(ReadListener readListener) {

    }
}

您还必须为您的文档 url 模式注册过滤器。

@Bean
public FilterRegistrationBean<DocsFormatterFilter> loggingFilter() {
    FilterRegistrationBean<DocsFormatterFilter> registrationBean = new FilterRegistrationBean<>();

    registrationBean.setFilter(new DocsFormatterFilter());
    registrationBean.addUrlPatterns("/v3/api-docs");

    return registrationBean;
}