mcopy: check for unsupported HEAD before failing request (#551)

Author: motz0815

src/main/java/me/itzg/helpers/http/FetchBuilderBase.java

@@ -1,12 +1,9 @@
 package me.itzg.helpers.http;
 
-import static io.netty.handler.codec.http.HttpHeaderNames.*;
+import static io.netty.handler.codec.http.HttpHeaderNames.ACCEPT;
+import static io.netty.handler.codec.http.HttpHeaderNames.AUTHORIZATION;
+import static io.netty.handler.codec.http.HttpHeaderNames.CONTENT_TYPE;
 
-import com.fasterxml.jackson.databind.ObjectMapper;
-import io.netty.handler.codec.http.HttpHeaderNames;
-import io.netty.handler.codec.http.HttpHeaders;
-import io.netty.handler.codec.http.HttpStatusClass;
-import io.netty.handler.codec.http.HttpUtil;
 import java.net.URI;
 import java.net.URISyntaxException;
 import java.nio.charset.StandardCharsets;
@@ -25,11 +22,19 @@
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 import java.util.stream.Collectors;
+
+import org.slf4j.Logger;
+
+import com.fasterxml.jackson.databind.ObjectMapper;
+
+import io.netty.handler.codec.http.HttpHeaderNames;
+import io.netty.handler.codec.http.HttpHeaders;
+import io.netty.handler.codec.http.HttpStatusClass;
+import io.netty.handler.codec.http.HttpUtil;
 import lombok.extern.slf4j.Slf4j;
 import me.itzg.helpers.errors.GenericException;
 import me.itzg.helpers.http.SharedFetch.Options;
 import me.itzg.helpers.json.ObjectMappers;
-import org.slf4j.Logger;
 import reactor.core.publisher.Mono;
 import reactor.netty.ByteBufMono;
 import reactor.netty.Connection;
@@ -246,12 +251,14 @@ protected boolean notExpectedContentType(HttpClientResponse resp) {
 
     /**
      * CDN providers like bukkit don't support HEAD and respond with a 200 OK and redirect to a path like /error?aspxerrorpath=/projects/worldedit/files/latest
+     * Also, S3 object storage services generally don't support HEAD and respond with 403 Forbidden when trying to fetch an object.
      * @param resp the response to evaluate
      * @return true if this response to a HEAD seems to indicate it is not supported
      */
     protected static boolean isHeadUnsupportedResponse(HttpClientResponse resp) {
-        return resp.path().equals("error") &&
-            HttpUtil.getMimeType(resp.responseHeaders().get(HttpHeaderNames.CONTENT_TYPE.toString())).equals("text/html");
+        return resp.status().code() == 403 ||
+            (resp.path().equals("error") &&
+            HttpUtil.getMimeType(resp.responseHeaders().get(HttpHeaderNames.CONTENT_TYPE.toString())).equals("text/html"));
     }
 
     protected <R> Mono<R> failedContentTypeMono(HttpClientResponse resp) {

src/main/java/me/itzg/helpers/http/OutputToDirectoryFetchBuilder.java

@@ -4,17 +4,19 @@
 import static io.netty.handler.codec.http.HttpHeaderNames.LAST_MODIFIED;
 import static java.util.Objects.requireNonNull;
 
-import io.netty.handler.codec.http.HttpHeaderNames;
-import io.netty.handler.codec.http.HttpResponseStatus;
 import java.io.IOException;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.time.Instant;
+
+import org.jetbrains.annotations.NotNull;
+
+import io.netty.handler.codec.http.HttpHeaderNames;
+import io.netty.handler.codec.http.HttpResponseStatus;
 import lombok.Setter;
 import lombok.experimental.Accessors;
 import lombok.extern.slf4j.Slf4j;
 import me.itzg.helpers.files.ReactiveFileUtils;
-import org.jetbrains.annotations.NotNull;
 import reactor.core.publisher.Mono;
 import reactor.core.scheduler.Schedulers;
 import reactor.netty.ByteBufFlux;
@@ -75,14 +77,14 @@ public Mono<Path> assemble() {
                 .head()
                 .uri(uri())
                 .responseSingle((resp, bodyMono) -> {
-                    if (notSuccess(resp)) {
-                        return failedRequestMono(resp, bodyMono, "Extracting filename");
-                    }
-
                     if (isHeadUnsupportedResponse(resp)) {
                         return assembleFileDownloadNameViaGet(client);
                     }
 
+                    if (notSuccess(resp)) {
+                        return failedRequestMono(resp, bodyMono, "Extracting filename");
+                    }
+
                     final Path outputFile = outputDirectory.resolve(extractFilename(resp));
                     final Instant lastModified = respLastModified(resp);