Source code

001package org.hl7.fhir.r4.utils.client.network;
002
003import okhttp3.*;
004import org.apache.commons.lang3.StringUtils;
005import org.hl7.fhir.exceptions.FHIRException;
006import org.hl7.fhir.r4.formats.IParser;
007import org.hl7.fhir.r4.formats.JsonParser;
008import org.hl7.fhir.r4.formats.XmlParser;
009import org.hl7.fhir.r4.model.Bundle;
010import org.hl7.fhir.r4.model.OperationOutcome;
011import org.hl7.fhir.r4.model.Resource;
012import org.hl7.fhir.r4.utils.ResourceUtilities;
013import org.hl7.fhir.r4.utils.client.EFhirClientException;
014import org.hl7.fhir.r4.utils.client.ResourceFormat;
015import org.hl7.fhir.utilities.settings.FhirSettings;
016
017
018import javax.annotation.Nonnull;
019import java.io.IOException;
020import java.util.List;
021import java.util.Map;
022import java.util.concurrent.TimeUnit;
023
024public class FhirRequestBuilder {
025
026  protected static final String HTTP_PROXY_USER = "http.proxyUser";
027  protected static final String HTTP_PROXY_PASS = "http.proxyPassword";
028  protected static final String HEADER_PROXY_AUTH = "Proxy-Authorization";
029  protected static final String LOCATION_HEADER = "location";
030  protected static final String CONTENT_LOCATION_HEADER = "content-location";
031  protected static final String DEFAULT_CHARSET = "UTF-8";
032  /**
033   * The singleton instance of the HttpClient, used for all requests.
034   */
035  private static OkHttpClient okHttpClient;
036  private final Request.Builder httpRequest;
037  private String resourceFormat = null;
038  private Headers headers = null;
039  private String message = null;
040  private int retryCount = 1;
041  /**
042   * The timeout quantity. Used in combination with {@link FhirRequestBuilder#timeoutUnit}.
043   */
044  private long timeout = 5000;
045  /**
046   * Time unit for {@link FhirRequestBuilder#timeout}.
047   */
048  private TimeUnit timeoutUnit = TimeUnit.MILLISECONDS;
049
050  /**
051   * {@link FhirLoggingInterceptor} for log output.
052   */
053  private FhirLoggingInterceptor logger = null;
054
055  public FhirRequestBuilder(Request.Builder httpRequest) {
056    this.httpRequest = httpRequest;
057  }
058
059  /**
060   * Adds necessary default headers, formatting headers, and any passed in {@link Headers} to the passed in
061   * {@link okhttp3.Request.Builder}
062   *
063   * @param request {@link okhttp3.Request.Builder} to add headers to.
064   * @param format  Expected {@link Resource} format.
065   * @param headers Any additional {@link Headers} to add to the request.
066   */
067  protected static void formatHeaders(Request.Builder request, String format, Headers headers) {
068    addDefaultHeaders(request, headers);
069    if (format != null) addResourceFormatHeaders(request, format);
070    if (headers != null) addHeaders(request, headers);
071  }
072
073  /**
074   * Adds necessary headers for all REST requests.
075   * <li>User-Agent : hapi-fhir-tooling-client</li>
076   * <li>Accept-Charset : {@link FhirRequestBuilder#DEFAULT_CHARSET}</li>
077   *
078   * @param request {@link Request.Builder} to add default headers to.
079   */
080  protected static void addDefaultHeaders(Request.Builder request, Headers headers) {
081    if (headers == null || !headers.names().contains("User-Agent")) {
082      request.addHeader("User-Agent", "hapi-fhir-tooling-client");
083    }
084    request.addHeader("Accept-Charset", DEFAULT_CHARSET);
085  }
086
087  /**
088   * Adds necessary headers for the given resource format provided.
089   *
090   * @param request {@link Request.Builder} to add default headers to.
091   */
092  protected static void addResourceFormatHeaders(Request.Builder request, String format) {
093    request.addHeader("Accept", format);
094    request.addHeader("Content-Type", format + ";charset=" + DEFAULT_CHARSET);
095  }
096
097  /**
098   * Iterates through the passed in {@link Headers} and adds them to the provided {@link Request.Builder}.
099   *
100   * @param request {@link Request.Builder} to add headers to.
101   * @param headers {@link Headers} to add to request.
102   */
103  protected static void addHeaders(Request.Builder request, Headers headers) {
104    headers.forEach(header -> request.addHeader(header.getFirst(), header.getSecond()));
105  }
106
107  /**
108   * Returns true if any of the {@link org.hl7.fhir.r4.model.OperationOutcome.OperationOutcomeIssueComponent} within the
109   * provided {@link OperationOutcome} have an {@link org.hl7.fhir.r4.model.OperationOutcome.IssueSeverity} of
110   * {@link org.hl7.fhir.r4.model.OperationOutcome.IssueSeverity#ERROR} or
111   * {@link org.hl7.fhir.r4.model.OperationOutcome.IssueSeverity#FATAL}
112   *
113   * @param oo {@link OperationOutcome} to evaluate.
114   * @return {@link Boolean#TRUE} if an error exists.
115   */
116  protected static boolean hasError(OperationOutcome oo) {
117    return (oo.getIssue().stream()
118      .anyMatch(issue -> issue.getSeverity() == OperationOutcome.IssueSeverity.ERROR
119        || issue.getSeverity() == OperationOutcome.IssueSeverity.FATAL));
120  }
121
122  /**
123   * Extracts the 'location' header from the passes in {@link Headers}. If no value for 'location' exists, the
124   * value for 'content-location' is returned. If neither header exists, we return null.
125   *
126   * @param headers {@link Headers} to evaluate
127   * @return {@link String} header value, or null if no location headers are set.
128   */
129  protected static String getLocationHeader(Headers headers) {
130    Map<String, List<String>> headerMap = headers.toMultimap();
131    if (headerMap.containsKey(LOCATION_HEADER)) {
132      return headerMap.get(LOCATION_HEADER).get(0);
133    } else if (headerMap.containsKey(CONTENT_LOCATION_HEADER)) {
134      return headerMap.get(CONTENT_LOCATION_HEADER).get(0);
135    } else {
136      return null;
137    }
138  }
139
140  /**
141   * We only ever want to have one copy of the HttpClient kicking around at any given time. If we need to make changes
142   * to any configuration, such as proxy settings, timeout, caches, etc, we can do a per-call configuration through
143   * the {@link OkHttpClient#newBuilder()} method. That will return a builder that shares the same connection pool,
144   * dispatcher, and configuration with the original client.
145   * </p>
146   * The {@link OkHttpClient} uses the proxy auth properties set in the current system properties. The reason we don't
147   * set the proxy address and authentication explicitly, is due to the fact that this class is often used in conjunction
148   * with other http client tools which rely on the system.properties settings to determine proxy settings. It's easier
149   * to keep the method consistent across the board. ...for now.
150   *
151   * @return {@link OkHttpClient} instance
152   */
153  protected OkHttpClient getHttpClient() {
154    if (FhirSettings.isProhibitNetworkAccess()) {
155      throw new FHIRException("Network Access is prohibited in this context");
156    }
157    
158    if (okHttpClient == null) {
159      okHttpClient = new OkHttpClient();
160    }
161
162    Authenticator proxyAuthenticator = getAuthenticator();
163
164    OkHttpClient.Builder builder = okHttpClient.newBuilder();
165    if (logger != null) builder.addInterceptor(logger);
166    builder.addInterceptor(new RetryInterceptor(retryCount));
167
168    return builder.connectTimeout(timeout, timeoutUnit)
169      .addInterceptor(new RetryInterceptor(retryCount))
170      .connectTimeout(timeout, timeoutUnit)
171      .writeTimeout(timeout, timeoutUnit)
172      .readTimeout(timeout, timeoutUnit)
173      .proxyAuthenticator(proxyAuthenticator)
174      .build();
175  }
176
177  @Nonnull
178  private static Authenticator getAuthenticator() {
179    return (route, response) -> {
180      final String httpProxyUser = System.getProperty(HTTP_PROXY_USER);
181      final String httpProxyPass = System.getProperty(HTTP_PROXY_PASS);
182      if (httpProxyUser != null && httpProxyPass != null) {
183        String credential = Credentials.basic(httpProxyUser, httpProxyPass);
184        return response.request().newBuilder()
185          .header(HEADER_PROXY_AUTH, credential)
186          .build();
187      }
188      return response.request().newBuilder().build();
189    };
190  }
191
192  public FhirRequestBuilder withResourceFormat(String resourceFormat) {
193    this.resourceFormat = resourceFormat;
194    return this;
195  }
196
197  public FhirRequestBuilder withHeaders(Headers headers) {
198    this.headers = headers;
199    return this;
200  }
201
202  public FhirRequestBuilder withMessage(String message) {
203    this.message = message;
204    return this;
205  }
206
207  public FhirRequestBuilder withRetryCount(int retryCount) {
208    this.retryCount = retryCount;
209    return this;
210  }
211
212  public FhirRequestBuilder withLogger(FhirLoggingInterceptor logger) {
213    this.logger = logger;
214    return this;
215  }
216
217  public FhirRequestBuilder withTimeout(long timeout, TimeUnit unit) {
218    this.timeout = timeout;
219    this.timeoutUnit = unit;
220    return this;
221  }
222
223  protected Request buildRequest() {
224    return httpRequest.build();
225  }
226
227  public <T extends Resource> ResourceRequest<T> execute() throws IOException {
228    formatHeaders(httpRequest, resourceFormat, headers);
229    Response response = getHttpClient().newCall(httpRequest.build()).execute();
230    T resource = unmarshalReference(response, resourceFormat);
231    return new ResourceRequest<T>(resource, response.code(), getLocationHeader(response.headers()));
232  }
233
234  public Bundle executeAsBatch() throws IOException {
235    formatHeaders(httpRequest, resourceFormat, null);
236    Response response = getHttpClient().newCall(httpRequest.build()).execute();
237    return unmarshalFeed(response, resourceFormat);
238  }
239
240  /**
241   * Unmarshalls a resource from the response stream.
242   */
243  @SuppressWarnings("unchecked")
244  protected <T extends Resource> T unmarshalReference(Response response, String format) {
245    T resource = null;
246    OperationOutcome error = null;
247
248    if (response.body() != null) {
249      try {
250        byte[] body = response.body().bytes();
251        resource = (T) getParser(format).parse(body);
252        if (resource instanceof OperationOutcome && hasError((OperationOutcome) resource)) {
253          error = (OperationOutcome) resource;
254        }
255      } catch (IOException ioe) {
256        throw new EFhirClientException("Error reading Http Response: " + ioe.getMessage(), ioe);
257      } catch (Exception e) {
258        throw new EFhirClientException("Error parsing response message: " + e.getMessage(), e);
259      }
260    }
261
262    if (error != null) {
263      throw new EFhirClientException("Error from server: " + ResourceUtilities.getErrorDescription(error), error);
264    }
265
266    return resource;
267  }
268
269  /**
270   * Unmarshalls Bundle from response stream.
271   */
272  protected Bundle unmarshalFeed(Response response, String format) {
273    Bundle feed = null;
274    OperationOutcome error = null;
275    try {
276      byte[] body = response.body().bytes();
277      String contentType = response.header("Content-Type");
278      if (body != null) {
279        if (contentType.contains(ResourceFormat.RESOURCE_XML.getHeader()) || contentType.contains(ResourceFormat.RESOURCE_JSON.getHeader()) || contentType.contains("text/xml+fhir")) {
280          Resource rf = getParser(format).parse(body);
281          if (rf instanceof Bundle)
282            feed = (Bundle) rf;
283          else if (rf instanceof OperationOutcome && hasError((OperationOutcome) rf)) {
284            error = (OperationOutcome) rf;
285          } else {
286            throw new EFhirClientException("Error reading server response: a resource was returned instead");
287          }
288        }
289      }
290    } catch (IOException ioe) {
291      throw new EFhirClientException("Error reading Http Response", ioe);
292    } catch (Exception e) {
293      throw new EFhirClientException("Error parsing response message", e);
294    }
295    if (error != null) {
296      throw new EFhirClientException("Error from server: " + ResourceUtilities.getErrorDescription(error), error);
297    }
298    return feed;
299  }
300
301  /**
302   * Returns the appropriate parser based on the format type passed in. Defaults to XML parser if a blank format is
303   * provided...because reasons.
304   * <p>
305   * Currently supports only "json" and "xml" formats.
306   *
307   * @param format One of "json" or "xml".
308   * @return {@link JsonParser} or {@link XmlParser}
309   */
310  protected IParser getParser(String format) {
311    if (StringUtils.isBlank(format)) {
312      format = ResourceFormat.RESOURCE_XML.getHeader();
313    }
314    if (format.equalsIgnoreCase("json") || format.equalsIgnoreCase(ResourceFormat.RESOURCE_JSON.getHeader())) {
315      return new JsonParser();
316    } else if (format.equalsIgnoreCase("xml") || format.equalsIgnoreCase(ResourceFormat.RESOURCE_XML.getHeader())) {
317      return new XmlParser();
318    } else {
319      throw new EFhirClientException("Invalid format: " + format);
320    }
321  }
322}