package cn.home1.oss.lib.common;
   
   import static cn.home1.oss.lib.common.RequestUtlis.findWrapper;
   import static com.google.common.collect.Lists.newArrayList;
   import static org.apache.commons.lang3.StringUtils.isBlank;
   import static org.apache.commons.lang3.StringUtils.isNotBlank;
   import static org.springframework.http.HttpHeaders.ACCEPT;
   import static org.springframework.http.HttpHeaders.AUTHORIZATION;
   import static org.springframework.http.HttpHeaders.CONTENT_TYPE;
  import static org.springframework.http.MediaType.ALL;
  import static org.springframework.http.MediaType.APPLICATION_FORM_URLENCODED;
  import static org.springframework.http.MediaType.APPLICATION_JSON;
  import static org.springframework.http.MediaType.APPLICATION_XML;
  import static org.springframework.http.MediaType.parseMediaType;
  
  import com.google.common.collect.ImmutableSet;
  
  import lombok.SneakyThrows;
  import lombok.extern.slf4j.Slf4j;
  
  import org.springframework.http.MediaType;
  import org.springframework.util.StreamUtils;
  import org.springframework.web.util.ContentCachingRequestWrapper;
  
  import java.io.IOException;
  import java.nio.charset.Charset;
  import java.util.Collection;
  import java.util.Enumeration;
  
  import javax.servlet.http.HttpServletRequest;
  
  /**
   * build curl from request
   *
   * <p>
   * Created by zhanghaolun on 16/7/4.
   * </p>
   */
  @Slf4j
  public abstract class CurlUtils {
  
    private CurlUtils() {
    }
  
    private static final Collection<String> RETAIN_HEADERS =
      ImmutableSet.copyOf(newArrayList(ACCEPT, CONTENT_TYPE, AUTHORIZATION));
  
    /**
     * 安置http请求, 生成curl命令.
     *
     * @param request {@link HttpServletRequest}
     * @return curl command
     */
    public static String curl(final HttpServletRequest request) {
      final String result;
      if (request != null) {
        final MediaType contentType =
          isNotBlank(request.getContentType()) ? parseMediaType(request.getContentType()) : ALL;
        final String headers = curlHeaders(request);
        final String parameters = curlParameters(request);
  
        final StringBuilder curl = new StringBuilder("curl ").append(headers).append(" ")
          .append("-X ").append(request.getMethod()).append(" ");
        if (APPLICATION_JSON.includes(contentType) || APPLICATION_XML.includes(contentType)) {
          curl.append("--data '").append(curlBody(request)).append("' ");
        } else if (APPLICATION_FORM_URLENCODED == contentType) {
          curl.append("--data '").append(parameters).append("' ");
        } else if (isNotBlank(parameters)) {
          curl.append('?').append(parameters).append(' ');
  
        }
        curl.append(request.getRequestURL());
        result = curl.toString();
      } else {
        result = "";
      }
      return result;
    }
  
    static String curlHeaders(final HttpServletRequest request) {
      @SuppressWarnings("rawtypes")
      final Enumeration headerNames = request.getHeaderNames();
      final StringBuilder hBuilder = new StringBuilder();
      while (headerNames.hasMoreElements()) {
        final String name = (String) headerNames.nextElement();
        final String value = request.getHeader(name);
        if (RETAIN_HEADERS.contains(name)) {
          hBuilder.append("-H '").append(name).append(": ").append(value).append("' ");
        }
      }
      return hBuilder.toString();
    }
  
    @SneakyThrows
    static String curlParameters(final HttpServletRequest request) {
      @SuppressWarnings("rawtypes")
      final Enumeration parameterNames = request.getParameterNames();
      final StringBuilder pBuilder = new StringBuilder();
      while (parameterNames.hasMoreElements()) {
       final String name = (String) parameterNames.nextElement();
       final String value = request.getParameter(name);
       pBuilder //
         .append('&') //
         .append(name) //
         .append('=') //
         .append(CodecUtils.urlEncode(value));
     }
     return pBuilder.length() > 0 ? pBuilder.substring(1) : "";
   }
 
   @SneakyThrows
   public static String curlBody(final HttpServletRequest request) {
     final Charset charset = RequestUtlis.findCharset(request);
     try {
       // read raw inputStream first. (may be has not been read, for example 404)
       final String raw = StreamUtils.copyToString(request.getInputStream(), charset);
       final String result;
       if (isBlank(raw)) { // if no content in raw inputStream, 那应该是读过了, try to read cached.
         final ContentCachingRequestWrapper wrapper = findWrapper(request, ContentCachingRequestWrapper.class);
         if (wrapper != null) {
           result = new String(((ContentCachingRequestWrapper) request).getContentAsByteArray(), charset);
         } else {
           result = "";
         }
       } else {
         result = raw;
       }
       return result;
     } catch (final IOException ex) {
       log.warn("error reading request body.", ex);
     }
     return "";
   }
 }