# JSON with Bytes as Base64 { #json-with-bytes-as-base64 }

If your app needs to receive and send JSON data, but you need to include binary data in it, you can encode it as base64.

## Base64 vs Files { #base64-vs-files }

Consider first if you can use [Request Files](../tutorial/request-files.md) for uploading binary data and [Custom Response - FileResponse](./custom-response.md#fileresponse--fileresponse-) for sending binary data, instead of encoding it in JSON.

	flag.StringVar(&certFile, "cert-file", "", "Path to TLS cert file")
}

func writeErrorResponse(w http.ResponseWriter, err error) {
	w.WriteHeader(http.StatusBadRequest)
	json.NewEncoder(w).Encode(map[string]string{
		"error": fmt.Sprintf("%v", err),
	})
}

type Result struct {
	Result bool `json:"result"`
}

func mainHandler(w http.ResponseWriter, r *http.Request) {
	body, err := io.ReadAll(r.Body)

        assertEquals(SmbComTransaction.TRANS2_GET_DFS_REFERRAL, dst[5]);
        assertEquals((byte) 0x00, dst[6]);
    }

    @Test
    @DisplayName("writeParametersWireFormat should encode request buffer")
    void testWriteParametersWireFormat() throws Exception {
        // Given
        String filename = "\\\\server\\share";
        trans2GetDfsReferral = new Trans2GetDfsReferral(mockConfig, filename);

        setField(cmd, "newOpLockLevel", (byte) 0x01);
        setField(cmd, "timeout", 3000L);
        // arrays of one lock and one unlock range
        LockingAndXRange lock = new LockingAndXRange(false);
        lock.encode(new byte[20], 0); // initialise fields by encoding to set pid etc (though not needed)
        setField(lock, "pid", 123);
        setField(lock, "byteOffset", 100L);
        setField(lock, "lengthInBytes", 200L);

        this.lengthInBytes = SMBUtil.readInt4(buffer, bufferIndex + 6);
        return 10;
    }

    /**
     * {@inheritDoc}
     *
     * @see jcifs.Encodable#encode(byte[], int)
     */
    @Override
    public int encode(final byte[] dst, final int dstIndex) {
        if (this.largeFile) {
            SMBUtil.writeInt2(this.pid, dst, dstIndex);

     */
    @Override
    public int getContextType() {
        return NEGO_CTX_PREAUTH_TYPE;
    }

    /**
     * {@inheritDoc}
     *
     * @see jcifs.Encodable#encode(byte[], int)
     */
    @Override
    public int encode(final byte[] dst, int dstIndex) {
        final int start = dstIndex;

        SMBUtil.writeInt2(this.hashAlgos != null ? this.hashAlgos.length : 0, dst, dstIndex);

     */
    @Override
    public int getContextType() {
        return NEGO_CTX_ENC_TYPE;
    }

    /**
     * {@inheritDoc}
     *
     * @see jcifs.Encodable#encode(byte[], int)
     */
    @Override
    public int encode(final byte[] dst, int dstIndex) {
        final int start = dstIndex;
        SMBUtil.writeInt2(this.ciphers != null ? this.ciphers.length : 0, dst, dstIndex);
        dstIndex += 2;

        this.fileName = new String(nameBytes, StandardCharsets.UTF_16LE);
        return bufferIndex - start;
    }

    /**
     * {@inheritDoc}
     *
     * @see jcifs.Encodable#encode(byte[], int)
     */
    @Override
    public int encode(final byte[] dst, int dstIndex) {
        final int start = dstIndex;
        dst[dstIndex] = (byte) (this.replaceIfExists ? 1 : 0);
        dstIndex += 8; // 7 Reserved

/// note | Détails techniques

Les données issues des formulaires sont normalement encodées avec le « type de média » `application/x-www-form-urlencoded`.

Mais lorsque le formulaire inclut des fichiers, il est encodé en `multipart/form-data`. Vous lirez la gestion des fichiers dans le chapitre suivant.

    public int getContextType() {
        return CONTEXT_ID;
    }

    /**
     * Get the context data
     *
     * @return encoded context data
     */
    public byte[] getData() {
        // Encode the context data
        byte[] data = new byte[20]; // 2 + 2 + 4 + 4 + 4 + 4

        int idx = 0;
        SMBUtil.writeInt2(transformCount, data, idx);
        idx += 2;
        SMBUtil.writeInt2(reserved1, data, idx);