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wing328 merged 3 commits into from
Feb 11, 2026
Merged

fix(java/feign): handle binary response types in ApiResponseDecoder #22939

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e5829c4
fix(java/feign): handle binary response types in ApiResponseDecoder
cziberpv Feb 10, 2026
0150317
fix: address code review feedback
cziberpv Feb 10, 2026
cb7ed8e
fix: regenerate feign-hc5 sample with updated ApiResponseDecoder
cziberpv Feb 10, 2026
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76 changes: 71 additions & 5 deletions ...les/openapi-generator/src/main/resources/Java/libraries/feign/ApiResponseDecoder.mustache
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Original file line number Diff line number Diff line change
Expand Up @@ -7,33 +7,99 @@ import feign.Response;
import feign.Types;
import feign.jackson.JacksonDecoder;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.nio.file.StandardCopyOption;
import java.util.Collection;
import java.util.Collections;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import {{modelPackage}}.ApiResponse;

public class ApiResponseDecoder extends JacksonDecoder {

private static final Pattern FILENAME_PATTERN =
Pattern.compile("filename=\"([^\"]+)\"|filename=([^\\s;]+)");

public ApiResponseDecoder(ObjectMapper mapper) {
super(mapper);
}

@Override
public Object decode(Response response, Type type) throws IOException {
//Detects if the type is an instance of the parameterized class ApiResponse
if (type instanceof ParameterizedType && Types.getRawType(type).isAssignableFrom(ApiResponse.class)) {
//The ApiResponse class has a single type parameter, the Dto class itself
Type responseBodyType = ((ParameterizedType) type).getActualTypeArguments()[0];
Object body = super.decode(response, responseBodyType);
Object body = isBinaryType(responseBodyType)
? decodeBinary(response, responseBodyType)
: super.decode(response, responseBodyType);
Map<String, Collection<String>> responseHeaders = Collections.unmodifiableMap(response.headers());
return new ApiResponse<>(response.status(), responseHeaders, body);
}

if (isBinaryType(type)) {
return decodeBinary(response, type);
}

return super.decode(response, type);
}

private boolean isBinaryType(Type type) {
Class<?> raw = Types.getRawType(type);
return File.class.isAssignableFrom(raw)
|| byte[].class.isAssignableFrom(raw)
|| InputStream.class.isAssignableFrom(raw);
}

private Object decodeBinary(Response response, Type type) throws IOException {
Class<?> raw = Types.getRawType(type);
if (response.body() == null) {
return null;
}
if (byte[].class.isAssignableFrom(raw)) {
return response.body().asInputStream().readAllBytes();
}
if (InputStream.class.isAssignableFrom(raw)) {
return response.body().asInputStream();
}
return downloadToTempFile(response);
}

private File downloadToTempFile(Response response) throws IOException {
String filename = extractFilename(response);
File file;
if (filename != null) {
// Sanitize: strip path components to prevent path traversal
String safeName = Paths.get(filename).getFileName().toString();
java.nio.file.Path tempDir = Files.createTempDirectory("feign-download");
file = Files.createFile(tempDir.resolve(safeName)).toFile();
tempDir.toFile().deleteOnExit();
} else {
//The response is not encapsulated in the ApiResponse, decode the Dto as normal
return super.decode(response, type);
file = Files.createTempFile("download-", "").toFile();
}
file.deleteOnExit();
try (InputStream is = response.body().asInputStream()) {
Files.copy(is, file.toPath(), StandardCopyOption.REPLACE_EXISTING);
}
return file;
}

private String extractFilename(Response response) {
Collection<String> dispositions = response.headers().get("Content-Disposition");
if (dispositions == null) return null;
for (String disposition : dispositions) {
Matcher m = FILENAME_PATTERN.matcher(disposition);
if (m.find()) {
// Group 1: quoted filename (may contain spaces), Group 2: unquoted token
return m.group(1) != null ? m.group(1) : m.group(2);
}
}
return null;
}
}
76 changes: 71 additions & 5 deletions ...ent/petstore/java/feign-hc5/src/main/java/org/openapitools/client/ApiResponseDecoder.java
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Original file line number Diff line number Diff line change
Expand Up @@ -18,33 +18,99 @@
import feign.Types;
import feign.jackson.JacksonDecoder;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.nio.file.StandardCopyOption;
import java.util.Collection;
import java.util.Collections;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.openapitools.client.model.ApiResponse;

public class ApiResponseDecoder extends JacksonDecoder {

private static final Pattern FILENAME_PATTERN =
Pattern.compile("filename=\"([^\"]+)\"|filename=([^\\s;]+)");

public ApiResponseDecoder(ObjectMapper mapper) {
super(mapper);
}

@Override
public Object decode(Response response, Type type) throws IOException {
//Detects if the type is an instance of the parameterized class ApiResponse
if (type instanceof ParameterizedType && Types.getRawType(type).isAssignableFrom(ApiResponse.class)) {
//The ApiResponse class has a single type parameter, the Dto class itself
Type responseBodyType = ((ParameterizedType) type).getActualTypeArguments()[0];
Object body = super.decode(response, responseBodyType);
Object body = isBinaryType(responseBodyType)
? decodeBinary(response, responseBodyType)
: super.decode(response, responseBodyType);
Map<String, Collection<String>> responseHeaders = Collections.unmodifiableMap(response.headers());
return new ApiResponse<>(response.status(), responseHeaders, body);
}

if (isBinaryType(type)) {
return decodeBinary(response, type);
}

return super.decode(response, type);
}

private boolean isBinaryType(Type type) {
Class<?> raw = Types.getRawType(type);
return File.class.isAssignableFrom(raw)
|| byte[].class.isAssignableFrom(raw)
|| InputStream.class.isAssignableFrom(raw);
}

private Object decodeBinary(Response response, Type type) throws IOException {
Class<?> raw = Types.getRawType(type);
if (response.body() == null) {
return null;
}
if (byte[].class.isAssignableFrom(raw)) {
return response.body().asInputStream().readAllBytes();
}
if (InputStream.class.isAssignableFrom(raw)) {
return response.body().asInputStream();
}
return downloadToTempFile(response);
}

private File downloadToTempFile(Response response) throws IOException {
String filename = extractFilename(response);
File file;
if (filename != null) {
// Sanitize: strip path components to prevent path traversal
String safeName = Paths.get(filename).getFileName().toString();
java.nio.file.Path tempDir = Files.createTempDirectory("feign-download");
file = Files.createFile(tempDir.resolve(safeName)).toFile();
tempDir.toFile().deleteOnExit();
} else {
//The response is not encapsulated in the ApiResponse, decode the Dto as normal
return super.decode(response, type);
file = Files.createTempFile("download-", "").toFile();
}
file.deleteOnExit();
try (InputStream is = response.body().asInputStream()) {
Files.copy(is, file.toPath(), StandardCopyOption.REPLACE_EXISTING);
}
return file;
}

private String extractFilename(Response response) {
Collection<String> dispositions = response.headers().get("Content-Disposition");
if (dispositions == null) return null;
for (String disposition : dispositions) {
Matcher m = FILENAME_PATTERN.matcher(disposition);
if (m.find()) {
// Group 1: quoted filename (may contain spaces), Group 2: unquoted token
return m.group(1) != null ? m.group(1) : m.group(2);
}
}
return null;
}
}
76 changes: 71 additions & 5 deletions ...tore/java/feign-no-nullable/src/main/java/org/openapitools/client/ApiResponseDecoder.java
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Original file line number Diff line number Diff line change
Expand Up @@ -18,33 +18,99 @@
import feign.Types;
import feign.jackson.JacksonDecoder;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.nio.file.StandardCopyOption;
import java.util.Collection;
import java.util.Collections;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.openapitools.client.model.ApiResponse;

public class ApiResponseDecoder extends JacksonDecoder {

private static final Pattern FILENAME_PATTERN =
Pattern.compile("filename=\"([^\"]+)\"|filename=([^\\s;]+)");

public ApiResponseDecoder(ObjectMapper mapper) {
super(mapper);
}

@Override
public Object decode(Response response, Type type) throws IOException {
//Detects if the type is an instance of the parameterized class ApiResponse
if (type instanceof ParameterizedType && Types.getRawType(type).isAssignableFrom(ApiResponse.class)) {
//The ApiResponse class has a single type parameter, the Dto class itself
Type responseBodyType = ((ParameterizedType) type).getActualTypeArguments()[0];
Object body = super.decode(response, responseBodyType);
Object body = isBinaryType(responseBodyType)
? decodeBinary(response, responseBodyType)
: super.decode(response, responseBodyType);
Map<String, Collection<String>> responseHeaders = Collections.unmodifiableMap(response.headers());
return new ApiResponse<>(response.status(), responseHeaders, body);
}

if (isBinaryType(type)) {
return decodeBinary(response, type);
}

return super.decode(response, type);
}

private boolean isBinaryType(Type type) {
Class<?> raw = Types.getRawType(type);
return File.class.isAssignableFrom(raw)
|| byte[].class.isAssignableFrom(raw)
|| InputStream.class.isAssignableFrom(raw);
}

private Object decodeBinary(Response response, Type type) throws IOException {
Class<?> raw = Types.getRawType(type);
if (response.body() == null) {
return null;
}
if (byte[].class.isAssignableFrom(raw)) {
return response.body().asInputStream().readAllBytes();
}
if (InputStream.class.isAssignableFrom(raw)) {
return response.body().asInputStream();
}
return downloadToTempFile(response);
}

private File downloadToTempFile(Response response) throws IOException {
String filename = extractFilename(response);
File file;
if (filename != null) {
// Sanitize: strip path components to prevent path traversal
String safeName = Paths.get(filename).getFileName().toString();
java.nio.file.Path tempDir = Files.createTempDirectory("feign-download");
file = Files.createFile(tempDir.resolve(safeName)).toFile();
tempDir.toFile().deleteOnExit();
} else {
//The response is not encapsulated in the ApiResponse, decode the Dto as normal
return super.decode(response, type);
file = Files.createTempFile("download-", "").toFile();
}
file.deleteOnExit();
try (InputStream is = response.body().asInputStream()) {
Files.copy(is, file.toPath(), StandardCopyOption.REPLACE_EXISTING);
}
return file;
}

private String extractFilename(Response response) {
Collection<String> dispositions = response.headers().get("Content-Disposition");
if (dispositions == null) return null;
for (String disposition : dispositions) {
Matcher m = FILENAME_PATTERN.matcher(disposition);
if (m.find()) {
// Group 1: quoted filename (may contain spaces), Group 2: unquoted token
return m.group(1) != null ? m.group(1) : m.group(2);
}
}
return null;
}
}
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