“Content-Disposition”的“文件名”中的 UTF-8 字符产生“IllegalArgumentException：意外字符”

问题描述 投票：0回答：3

是否可以从 okhttp3 客户端发送 UTF-8 字符？

对于以下字符串：

String fileName = "3$ Mù F'RANçé_33902_Country_5_202105";
String contentDisposition = "attachment;filename=" + "\"" +  fileName + "\"";

我已经尝试过（对于 contentDisposition 标头）：

Headers headers = new Headers.Builder()
                       .addUnsafeNonAscii("Content-Disposition", contentDisposition)
                       .add("Authorization", bearer)
                       .add("Content-type", "application/octet-stream")
                       .build();
             Request request = new Request.Builder()
                     .headers(headers)
                     .post(requestBody) 
                     .url(urlAddress)
                     .build();

但是服务器收到：

3$ Mù F'RANçé_33902_Country_5_202105

此请求发送给固定合作伙伴，因此我无法访问后端。

application/octet-stream
是后端需要的。

身体是这样创建的：

byte[] data = FileUtils.readFileToByteArray(file);
RequestBody requestBody = RequestBody.create(data);

它与 Postman 完美配合。

完整的 MVCE（无法包含文件和后端信息，但它之前崩溃了，无论如何，所以你可以启动这个确切的代码，它应该会抛出错误）：

public class App 
{
    public static void main( String[] args ) throws IOException
    {
                OkHttpClient client = new OkHttpClient().newBuilder()
                    .build();
                MediaType mediaType = MediaType.parse("application/octet-stream");
                RequestBody body = RequestBody.create(mediaType, "");
                Request request = new Request.Builder()
                  .url("xxxx")
                  .method("POST", body)
                  .addHeader("Content-Type", "application/octet-stream")
                  .addHeader("content-disposition", "attachment;filename=\"3$ Mù F'RANçé_33902_Country_5_202105.csv\"")
                  .addHeader("Authorization", "Bearer xxxxx")
                  .addHeader("Cookie", "xxxxxx")
                  .build();
                Response response = client.newCall(request).execute();
    }
}

收到错误：

java.lang.IllegalArgumentException: Unexpected char 0xf9 at 25 in content-disposition value: attachment;filename="3$ Mù F'RANçé_33902_Country_5_202105.csv"

好的http版本：

5.0.0-alpha.2

我错过了什么吗？

谢谢

java http-headers okhttp
3个回答
17
投票

HTTP 标头的默认字符集是 ISO-8859-1。然而，有 RFC 6266，描述了如何在 

Content-Disposition
标头中对文件名进行编码。基本上，您指定字符集名称，然后对 UTF-8 字符进行百分比编码。您使用以 
fileName="my-simple-filename"
开头的参数，而不是 
filename*=utf-8''
，例如 

import java.net.URLEncoder;

// ...

String fileName = "3$ Mù F'RANçé_33902_Country_5_202105";
String contentDisposition = "attachment;filename*=utf-8''" + encodeFileName(fileName);

// ...

private static String encodeFileName(String fileName) throws UnsupportedEncodingException {
  return URLEncoder.encode(fileName, "UTF-8").replace("+", "%20");
}

使用 URL 编码器，然后修改“+”的结果是我在 here 发现的一个廉价技巧，如果您想避免使用 Guava、Spring 的 

ContentDisposition
class 或任何其他库，而只需使用 JRE 类。

更新： 这是完整的 MCVE，展示了如何将 UTF-8 字符串作为 POST 正文和内容处置文件名发送。演示服务器展示了如何手动解码该标头 - 通常 HTTP 服务器应该自动执行此操作。

Maven POM 显示使用的依赖项：

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>org.example</groupId>
  <artifactId>SO_Java_OkHttp3SendUtf8_70804280</artifactId>
  <version>1.0-SNAPSHOT</version>

  <properties>
    <maven.compiler.source>11</maven.compiler.source>
    <maven.compiler.target>11</maven.compiler.target>
  </properties>

  <dependencies>
    <dependency>
      <groupId>com.squareup.okhttp3</groupId>
      <artifactId>okhttp</artifactId>
      <version>4.9.3</version>
    </dependency>
    <dependency>
      <groupId>org.nanohttpd</groupId>
      <artifactId>nanohttpd</artifactId>
      <version>2.3.1</version>
    </dependency>
  </dependencies>

</project>

OkHttp 演示客户端：

import okhttp3.Headers;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.RequestBody;
import okhttp3.Response;

import java.io.IOException;
import java.net.URL;
import java.net.URLEncoder;
import java.nio.charset.StandardCharsets;
import java.util.Objects;

public class Client {
  public static void main(String[] args) throws IOException {
    String fileName = "3$ Mù F'RANçé_33902_Country_5_202105";
    String contentDisposition = "attachment;filename*=utf-8''" + encodeFileName(fileName);
    RequestBody requestBody = RequestBody.create(fileName.getBytes(StandardCharsets.UTF_8));
    Headers headers = new Headers.Builder()
      .add("Content-Disposition", contentDisposition)
      .add("Content-type", "application/octet-stream; charset=utf-8")
      .build();
    Request request = new Request.Builder()
      .headers(headers)
      .post(requestBody)
      .url(new URL("http://localhost:8080/"))
      .build();
    OkHttpClient client = new OkHttpClient();
    Response response = client.newCall(request).execute();
    System.out.println(Objects.requireNonNull(response.body()).string());
  }

  private static String encodeFileName(String fileName) {
    return URLEncoder.encode(fileName, StandardCharsets.UTF_8).replace("+", "%20");
  }
}

NanoHTTPD 演示服务器：

import fi.iki.elonen.NanoHTTPD;

import java.io.IOException;
import java.net.URLDecoder;
import java.nio.charset.StandardCharsets;
import java.util.HashMap;
import java.util.Map;

public class Server extends NanoHTTPD {

  public Server() throws IOException {
    super(8080);
    start(NanoHTTPD.SOCKET_READ_TIMEOUT, false);
    System.out.println("\nRunning! Point your browsers to http://localhost:8080/ \n");
  }

  public static void main(String[] args) throws IOException {
    new Server();
  }

  private static final String UTF_8_FILE_NAME_PREFIX = ";filename*=utf-8''";
  private static final int UTF_8_FILE_NAME_PREFIX_LENGTH = UTF_8_FILE_NAME_PREFIX.length();

  @Override
  public Response serve(IHTTPSession session) {
    try {
      Map<String, String> files = new HashMap<>();
      session.parseBody(files);
      String postBody = files.get("postData");
      String contentDisposition = session.getHeaders().get("content-disposition");
      String fileName = decodeFileName(
        contentDisposition.substring(
          contentDisposition.indexOf(UTF_8_FILE_NAME_PREFIX) + UTF_8_FILE_NAME_PREFIX_LENGTH
        )
      );
      System.out.println("POST body:           " + postBody);
      System.out.println("Content disposition: " + contentDisposition);
      System.out.println("UTF-8 file name:     " + fileName);
      return newFixedLengthResponse(postBody + "\n" + fileName);
    }
    catch (IOException | ResponseException e) {
      e.printStackTrace();
      return newFixedLengthResponse(e.toString());
    }
  }

  private static String decodeFileName(String fileName) {
    return URLDecoder.decode(fileName.replace("%20", "+"), StandardCharsets.UTF_8);
  }

}

如果先运行服务器，然后运行客户端，您将在服务器控制台上看到以下内容：

Running! Point your browsers to http://localhost:8080/ 

POST body:           3$ Mù F'RANçé_33902_Country_5_202105
Content disposition: attachment;filename*=utf-8''3%24%20M%C3%B9%20F%27RAN%C3%A7%C3%A9_33902_Country_5_202105
UTF-8 file name:     3$ Mù F'RANçé_33902_Country_5_202105

在客户端控制台上，您会看到：

3$ Mù F'RANçé_33902_Country_5_202105
3$ Mù F'RANçé_33902_Country_5_202105
4
投票

使用 spring 框架并遇到此错误的人可以执行以下操作：

HttpHeaders httpHeaders = new HttpHeaders();
ContentDisposition contentDisposition = ContentDisposition.builder("attachment")
    .filename("filename with unicode chars.csv", StandardCharsets.UTF_8).build();
httpHeaders.setContentDisposition(contentDisposition);
return ResponseEntity.ok().headers(httpHeaders)
    .contentType(MediaType.TEXT_PLAIN).body(byteArrayResourceObj);
0
投票

对于任何进入此线程的人，这里有有关该主题的更多信息，以及遵循 RFC 2396 的通用解决方案。

首先，这是当前 JAVA 主分支的 URLEncoder.java 类的注释：

    /* The list of characters that are not encoded has been
     * determined as follows:
     *
     * RFC 2396 states:
     * -----
     * Data characters that are allowed in a URI but do not have a
     * reserved purpose are called unreserved.  These include upper
     * and lower case letters, decimal digits, and a limited set of
     * punctuation marks and symbols.
     *
     * unreserved  = alphanum | mark
     *
     * mark        = "-" | "_" | "." | "!" | "~" | "*" | "'" | "(" | ")"
     *
     * Unreserved characters can be escaped without changing the
     * semantics of the URI, but this should not be done unless the
     * URI is being used in a context that does not allow the
     * unescaped character to appear.
     * -----
     *
     * It appears that both Netscape and Internet Explorer escape
     * all special characters from this list with the exception
     * of "-", "_", ".", "*". While it is not clear why they are
     * escaping the other characters, perhaps it is safest to
     * assume that there might be contexts in which the others
     * are unsafe if not escaped. Therefore, we will use the same
     * list. It is also noteworthy that this is consistent with
     * O'Reilly's "HTML: The Definitive Guide" (page 164).
     *
     * As a last note, Internet Explorer does not encode the "@"
     * character which is clearly not unreserved according to the
     * RFC. We are being consistent with the RFC in this matter,
     * as is Netscape.
     *
     */

这意味着当前的 JAVA 代码库对于要编码的字符非常有意见，并且由于与 Internet Explorer 和 Netscape 浏览器的兼容性考虑而与 RFC 规范背道而驰。这对我来说似乎非常过时了。因此，为了获得有效的 RFC 2396 编码，我们只需将过时的编码字符串替换回原始字符即可：

fun encodeRFC2396(string: String): String =
    java.net.URLEncoder.encode(string, Charsets.UTF_8)
        .replace("+", " ")
        .replace("%7E", "~")
        .replace("%21", "!")
        .replace("%2A", "*")
        .replace("%27", "'")
        .replace("%28", "(")
        .replace("%29", ")")

然后就可以轻松构建 Content-Disposition 标头了：

val filename = "täöüst-_.!~*'( 1 ).txt"
val contentDispositionHeader =
    "Content-Disposition: attachment;filename*=utf-8''${encodeRFC2396(filename)}"
println(contentDispositionHeader)
// Content-Disposition: attachment;filename*=utf-8''t%C3%A4%C3%B6%C3%BCst-_.!~*'( 1 ).txt
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