Do not send Content-Type header with GET requests

org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/utils/client/FHIRToolingClient.java

@@ -162,7 +162,7 @@ public class FHIRToolingClient extends FHIRBaseToolingClient {
       try {
         T output =  (T) client.issueGetResourceRequest(resourceUri,
           withVer(preferredResourceFormat.getHeader(), "5.0"),
-          generateHeaders(),
+          generateHeaders(false),
           message,
           timeoutNormal).getReference();
         if (attemptedResourceFormat != preferredResourceFormat) {
@@ -214,7 +214,7 @@ public class FHIRToolingClient extends FHIRBaseToolingClient {
     ResourceRequest<Resource> result = null;
     try {
       result = client.issueGetResourceRequest(resourceAddress.resolveGetUriFromResourceClassAndId(resourceClass, id),
-          withVer(getPreferredResourceFormat(), "4.0"), generateHeaders(), "Read " + resourceClass + "/" + id,
+          withVer(getPreferredResourceFormat(), "4.0"), generateHeaders(false), "Read " + resourceClass + "/" + id,
           timeoutNormal);
       if (result.isUnsuccessfulRequest()) {
         throw new EFhirClientException("Server returned error code " + result.getHttpStatus(),
@@ -233,7 +233,7 @@ public class FHIRToolingClient extends FHIRBaseToolingClient {
     try {
       result = client.issueGetResourceRequest(resourceAddress.resolveGetUriFromResourceClassAndId(resourceClass, id),
         withVer(getPreferredResourceFormat(), "4.0"),
-        generateHeaders(),
+        generateHeaders(false),
         "Read " + resourceClass.getName() + "/" + id,
         timeoutNormal);
       if (result.isUnsuccessfulRequest()) {
@@ -251,7 +251,7 @@ public class FHIRToolingClient extends FHIRBaseToolingClient {
     try {
       result = client.issueGetResourceRequest(resourceAddress.resolveGetUriFromResourceClassAndIdAndVersion(resourceClass, id, version),
         withVer(getPreferredResourceFormat(), "4.0"),
-        generateHeaders(),
+        generateHeaders(false),
         "VRead " + resourceClass.getName() + "/" + id + "/?_history/" + version,
         timeoutNormal);
       if (result.isUnsuccessfulRequest()) {
@@ -269,7 +269,7 @@ public class FHIRToolingClient extends FHIRBaseToolingClient {
     try {
       result = client.issueGetResourceRequest(resourceAddress.resolveGetUriFromResourceClassAndCanonical(resourceClass, canonicalURL),
         withVer(getPreferredResourceFormat(), "4.0"),
-        generateHeaders(),
+        generateHeaders(false),
         "Read " + resourceClass.getName() + "?url=" + canonicalURL,
         timeoutNormal);
       if (result.isUnsuccessfulRequest()) {
@@ -293,7 +293,7 @@ public class FHIRToolingClient extends FHIRBaseToolingClient {
       result = client.issuePutRequest(resourceAddress.resolveGetUriFromResourceClassAndId(resource.getClass(), resource.getId()),
         ByteUtils.resourceToByteArray(resource, false, isJson(getPreferredResourceFormat()), false),
         withVer(getPreferredResourceFormat(), "4.0"),
-        generateHeaders(),
+        generateHeaders(true),
         "Update " + resource.fhirType() + "/" + resource.getId(),
         timeoutOperation);
       if (result.isUnsuccessfulRequest()) {
@@ -321,7 +321,7 @@ public class FHIRToolingClient extends FHIRBaseToolingClient {
       result = client.issuePutRequest(resourceAddress.resolveGetUriFromResourceClassAndId(resourceClass, id),
         ByteUtils.resourceToByteArray(resource, false, isJson(getPreferredResourceFormat()), false),
         withVer(getPreferredResourceFormat(), "4.0"),
-        generateHeaders(),
+        generateHeaders(true),
         "Update " + resource.fhirType() + "/" + id,
         timeoutOperation);
       if (result.isUnsuccessfulRequest()) {
@@ -357,10 +357,10 @@ public class FHIRToolingClient extends FHIRBaseToolingClient {
       URI url = resourceAddress.resolveOperationURLFromClass(resourceClass, name, ps);
       if (complex) {
         byte[] body = ByteUtils.resourceToByteArray(params, false, isJson(getPreferredResourceFormat()), true);
-        result = client.issuePostRequest(url, body, withVer(getPreferredResourceFormat(), "4.0"), generateHeaders(),
+        result = client.issuePostRequest(url, body, withVer(getPreferredResourceFormat(), "4.0"), generateHeaders(true),
             "POST " + resourceClass.getName() + "/$" + name, timeoutLong);
       } else {
-        result = client.issueGetResourceRequest(url, withVer(getPreferredResourceFormat(), "4.0"), generateHeaders(), "GET " + resourceClass.getName() + "/$" + name, timeoutLong);
+        result = client.issueGetResourceRequest(url, withVer(getPreferredResourceFormat(), "4.0"), generateHeaders(false), "GET " + resourceClass.getName() + "/$" + name, timeoutLong);
       }
       if (result.isUnsuccessfulRequest()) {
         throw new EFhirClientException("Server returned error code " + result.getHttpStatus(), (OperationOutcome) result.getPayload());
@@ -383,7 +383,7 @@ public class FHIRToolingClient extends FHIRBaseToolingClient {
     Bundle transactionResult = null;
     try {
       transactionResult = client.postBatchRequest(resourceAddress.getBaseServiceUri(), ByteUtils.resourceToByteArray(batch, false, isJson(getPreferredResourceFormat()), false), withVer(getPreferredResourceFormat(), "4.0"),
-          generateHeaders(),
+          generateHeaders(true),
           "transaction", timeoutOperation + (timeoutEntry * batch.getEntry().size()));
     } catch (Exception e) {
       handleException("An error occurred trying to process this transaction request", e);
@@ -398,7 +398,7 @@ public class FHIRToolingClient extends FHIRBaseToolingClient {
     try {
       result = client.issuePostRequest(resourceAddress.resolveValidateUri(resourceClass, id),
         ByteUtils.resourceToByteArray(resource, false, isJson(getPreferredResourceFormat()), false),
-        withVer(getPreferredResourceFormat(), "4.0"), generateHeaders(),
+        withVer(getPreferredResourceFormat(), "4.0"), generateHeaders(true),
         "POST " + resourceClass.getName() + (id != null ? "/" + id : "") + "/$validate", timeoutLong);
       if (result.isUnsuccessfulRequest()) {
         throw new EFhirClientException("Server returned error code " + result.getHttpStatus(), (OperationOutcome) result.getPayload());
@@ -458,7 +458,7 @@ public class FHIRToolingClient extends FHIRBaseToolingClient {
       result = client.issuePostRequest(resourceAddress.resolveOperationUri(ValueSet.class, "expand"),
           ByteUtils.resourceToByteArray(p, false, isJson(getPreferredResourceFormat()), true),
           withVer(getPreferredResourceFormat(), "4.0"),
-          generateHeaders(),
+          generateHeaders(true),
           "ValueSet/$expand?url=" + source.getUrl(),
           timeoutExpand);
     } catch (IOException e) {
@@ -476,7 +476,7 @@ public class FHIRToolingClient extends FHIRBaseToolingClient {
     try {
       result = client.issueGetResourceRequest(resourceAddress.resolveOperationUri(CodeSystem.class, "lookup", params),
         withVer(getPreferredResourceFormat(), "4.0"),
-        generateHeaders(),
+        generateHeaders(false),
         "CodeSystem/$lookup",
         timeoutNormal);
     } catch (IOException e) {
@@ -495,7 +495,7 @@ public class FHIRToolingClient extends FHIRBaseToolingClient {
       result = client.issuePostRequest(resourceAddress.resolveOperationUri(CodeSystem.class, "lookup"),
           ByteUtils.resourceToByteArray(p, false, isJson(getPreferredResourceFormat()), true),
         withVer(getPreferredResourceFormat(), "4.0"),
-        generateHeaders(),
+        generateHeaders(true),
         "CodeSystem/$lookup",
         timeoutNormal);
     } catch (IOException e) {
@@ -514,7 +514,7 @@ public class FHIRToolingClient extends FHIRBaseToolingClient {
       result = client.issuePostRequest(resourceAddress.resolveOperationUri(ConceptMap.class, "translate"),
           ByteUtils.resourceToByteArray(p, false, isJson(getPreferredResourceFormat()), true),
         withVer(getPreferredResourceFormat(), "4.0"),
-        generateHeaders(),
+        generateHeaders(true),
         "ConceptMap/$translate",
         timeoutNormal);
     } catch (IOException e) {
@@ -539,7 +539,7 @@ public class FHIRToolingClient extends FHIRBaseToolingClient {
       result = client.issuePostRequest(resourceAddress.resolveOperationUri(null, "closure", new HashMap<String, String>()),
         ByteUtils.resourceToByteArray(params, false, isJson(getPreferredResourceFormat()), true),
         withVer(getPreferredResourceFormat(), "4.0"),
-        generateHeaders(),
+        generateHeaders(true),
         "Closure?name=" + name,
         timeoutNormal);
       if (result.isUnsuccessfulRequest()) {
@@ -561,7 +561,7 @@ public class FHIRToolingClient extends FHIRBaseToolingClient {
       result = client.issuePostRequest(resourceAddress.resolveOperationUri(null, "closure", new HashMap<String, String>()),
         ByteUtils.resourceToByteArray(params, false, isJson(getPreferredResourceFormat()), true),
         withVer(getPreferredResourceFormat(), "4.0"),
-        generateHeaders(),
+        generateHeaders(true),
         "UpdateClosure?name=" + name,
         timeoutOperation);
       if (result.isUnsuccessfulRequest()) {
@@ -617,7 +617,7 @@ public class FHIRToolingClient extends FHIRBaseToolingClient {
     this.headers = headers;
   }
 
-  private Headers generateHeaders() {
+  private Headers generateHeaders(boolean hasBody) {
     Headers.Builder builder = new Headers.Builder();
     // Add basic auth header if it exists
     if (basicAuthHeaderExists()) {
@@ -635,7 +635,7 @@ public class FHIRToolingClient extends FHIRBaseToolingClient {
       builder.add("Accept-Language: "+acceptLang);
     }
     
-    if (!Utilities.noString(contentLang)) {
+    if (hasBody && !Utilities.noString(contentLang)) {
       builder.add("Content-Language: "+contentLang);
     }
     
@@ -689,7 +689,7 @@ public class FHIRToolingClient extends FHIRBaseToolingClient {
     org.hl7.fhir.r5.utils.client.network.ResourceRequest<Resource> result = null;
     try {
       result = client.issueGetResourceRequest(resourceAddress.resolveGetResource(resourceClass, id),
-          withVer(getPreferredResourceFormat(), "4.0"), generateHeaders(), resourceClass.getName()+"/"+id, timeoutNormal);
+          withVer(getPreferredResourceFormat(), "4.0"), generateHeaders(false), resourceClass.getName()+"/"+id, timeoutNormal);
     } catch (IOException e) {
       throw new FHIRException(e);
     }

org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/utils/client/network/FhirRequestBuilder.java

@@ -13,6 +13,7 @@ import org.hl7.fhir.r5.utils.ResourceUtilities;
 import org.hl7.fhir.r5.utils.client.EFhirClientException;
 import org.hl7.fhir.r5.utils.client.ResourceFormat;
 import org.hl7.fhir.utilities.MimeType;
+import org.hl7.fhir.utilities.Utilities;
 import org.hl7.fhir.utilities.settings.FhirSettings;
 
 import javax.annotation.Nonnull;
@@ -91,7 +92,9 @@ public class FhirRequestBuilder {
    */
   protected static void addResourceFormatHeaders(Request.Builder request, String format) {
     request.addHeader("Accept", format);
-    request.addHeader("Content-Type", format + ";charset=" + DEFAULT_CHARSET);
+    if (Utilities.existsInList(request.getMethod$okhttp(), "POST", "PUT")) {
+      request.addHeader("Content-Type", format + ";charset=" + DEFAULT_CHARSET);
+    }
   }
 
   /**

org.hl7.fhir.r5/src/test/java/org/hl7/fhir/r5/utils/client/network/FhirRequestBuilderTest.java

@@ -26,10 +26,27 @@ class FhirRequestBuilderTest {
   }
 
   @Test
-  @DisplayName("Test resource format headers are added correctly.")
-  void addResourceFormatHeaders() {
+  @DisplayName("Test resource format headers are added correctly (GET).")
+  void addResourceFormatHeadersGET() {
     String testFormat = "yaml";
     Request.Builder request = new Request.Builder().url("http://www.google.com");
+    request.setMethod$okhttp("GET");
+    FhirRequestBuilder.addResourceFormatHeaders(request, testFormat);
+
+    Map<String, List<String>> headersMap = request.build().headers().toMultimap();
+    Assertions.assertNotNull(headersMap.get("Accept"), "Accept header null.");
+    Assertions.assertEquals(testFormat, headersMap.get("Accept").get(0),
+      "Accept header not populated with expected value " + testFormat + ".");
+
+    Assertions.assertNull(headersMap.get("Content-Type"), "Content-Type header not null.");
+  }
+
+  @Test
+  @DisplayName("Test resource format headers are added correctly (POST).")
+  void addResourceFormatHeadersPOST() {
+    String testFormat = "yaml";
+    Request.Builder request = new Request.Builder().url("http://www.google.com");
+    request.setMethod$okhttp("POST");
     FhirRequestBuilder.addResourceFormatHeaders(request, testFormat);
 
     Map<String, List<String>> headersMap = request.build().headers().toMultimap();