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How to Write a Route Filter

Pragya Keshap answered on February 17, 2023 Popularity 3/10 Helpfulness 1/10

answer How to Write a Route Filter

How to Write a Route Filter

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public class OkHttpRoutingFilter extends ZuulFilter {
	@Autowired
	private ProxyRequestHelper helper;

	@Override
	public String filterType() {
		return ROUTE_TYPE;
	}

	@Override
	public int filterOrder() {
		return SIMPLE_HOST_ROUTING_FILTER_ORDER - 1;
	}

	@Override
	public boolean shouldFilter() {
		return RequestContext.getCurrentContext().getRouteHost() != null
				&& RequestContext.getCurrentContext().sendZuulResponse();
	}

    @Override
    public Object run() {
		OkHttpClient httpClient = new OkHttpClient.Builder()
				// customize
				.build();

		RequestContext context = RequestContext.getCurrentContext();
		HttpServletRequest request = context.getRequest();

		String method = request.getMethod();

		String uri = this.helper.buildZuulRequestURI(request);

		Headers.Builder headers = new Headers.Builder();
		Enumeration<String> headerNames = request.getHeaderNames();
		while (headerNames.hasMoreElements()) {
			String name = headerNames.nextElement();
			Enumeration<String> values = request.getHeaders(name);

			while (values.hasMoreElements()) {
				String value = values.nextElement();
				headers.add(name, value);
			}
		}

		InputStream inputStream = request.getInputStream();

		RequestBody requestBody = null;
		if (inputStream != null && HttpMethod.permitsRequestBody(method)) {
			MediaType mediaType = null;
			if (headers.get("Content-Type") != null) {
				mediaType = MediaType.parse(headers.get("Content-Type"));
			}
			requestBody = RequestBody.create(mediaType, StreamUtils.copyToByteArray(inputStream));
		}

		Request.Builder builder = new Request.Builder()
				.headers(headers.build())
				.url(uri)
				.method(method, requestBody);

		Response response = httpClient.newCall(builder.build()).execute();

		LinkedMultiValueMap<String, String> responseHeaders = new LinkedMultiValueMap<>();

		for (Map.Entry<String, List<String>> entry : response.headers().toMultimap().entrySet()) {
			responseHeaders.put(entry.getKey(), entry.getValue());
		}

		this.helper.setResponse(response.code(), response.body().byteStream(),
				responseHeaders);
		context.setRouteHost(null); // prevent SimpleHostRoutingFilter from running
		return null;
    }
}

Popularity 3/10 Helpfulness 1/10 Language java

Source: cloud.spring.io

Tags: filter java

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Contributed on Feb 17 2023

Pragya Keshap

0 Answers Avg Quality 2/10

How to Write a Route Filter

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