```
curl -u <CLIENT_ID>:<CLIENT_SECRET> -k -d "grant_type=client_credentials" -H "Content-Type:application/x-www-form-urlencoded" https://<IS_HOST>:<IS_HTTPS_PORT>/oauth2/token
```

Example:

```
curl -u PoEgXP6uVO45IsENRngDXj5Au5Ya:eKsw6z8CtOJVBtrOWvhRWL4TUCga -k -d "grant_type=client_credentials" -H "Content-Type:application/x-www-form-urlencoded" https://localhost:9443/oauth2/token
```

**FastAPI** will make sure to read that data from the right place instead of JSON.

/// note | Technical Details

Data from forms is normally encoded using the "media type" `application/x-www-form-urlencoded`.

But when the form includes files, it is encoded as `multipart/form-data`. You'll read about handling files in the next chapter.

**FastAPI** will make sure to read that data from the right place instead of JSON.

/// note | Technical Details

Data from forms is normally encoded using the "media type" `application/x-www-form-urlencoded` when it doesn't include files.

But when the form includes files, it is encoded as `multipart/form-data`. If you use `File`, **FastAPI** will know it has to get the files from the correct part of the body.

 */
package org.codelibs.fess.sso.aad;

import static org.codelibs.core.stream.StreamUtil.split;

import java.io.IOException;
import java.net.URI;
import java.net.URLEncoder;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Locale;
import java.util.Map;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.net.InetAddress;
import java.net.URLEncoder;
import java.net.UnknownHostException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.time.Instant;
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.util.ArrayList;

	// Assume roles with no JWT, handles AssumeRole.
	stsRouter.Methods(http.MethodPost).MatcherFunc(func(r *http.Request, rm *mux.RouteMatch) bool {
		ctypeOk := wildcard.MatchSimple("application/x-www-form-urlencoded*", r.Header.Get(xhttp.ContentType))
		authOk := wildcard.MatchSimple(signV4Algorithm+"*", r.Header.Get(xhttp.Authorization))
		noQueries := len(r.URL.RawQuery) == 0
		return ctypeOk && authOk && noQueries

	if err != nil {
		return "", fmt.Errorf("new request err (/login): %v", err)
	}
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	_, err = dexClient.Do(req)
	if err != nil {
		return "", fmt.Errorf("post form err: %v", err)
	}
	// fmt.Printf("resp: %#v %#v\n", resp.StatusCode, resp.Header)
	// bodyBuf, err := io.ReadAll(resp.Body)