http-api support AtAll

mirai-api-http/README_CH.md

@@ -343,9 +343,10 @@ Content-Type：multipart/form-data
 #### 消息是构成消息链的基本对象，目前支持的消息类型有
 
 + [x] At，@消息
++ [x] AtAll，@全体成员
 + [x] Face，表情消息
 + [x] Plain，文字消息
-+ [ ] Image，图片消息
++ [x] Image，图片消息
 + [ ] Xml，Xml卡片消息
 + [ ] 敬请期待
 
@@ -364,6 +365,18 @@ Content-Type：multipart/form-data
 | target  | Long   | 群员QQ号                  |
 | display | String | @时显示的文本如："@Mirai" |
 
+#### AtAll
+
+```json5
+{
+    "type": "AtAll"
+}
+```
+
+| 名字    | 类型   | 说明                      |
+| ------- | ------ | ------------------------- |
+| -       | -      | -                         |
+
 #### Face
 
 ```json5

mirai-api-http/src/main/kotlin/net/mamoe/mirai/api/http/data/common/MessageDTO.kt

@@ -39,6 +39,9 @@ data class UnKnownMessagePacketDTO(val msg: String) : MessagePacketDTO()
 @SerialName("At")
 data class AtDTO(val target: Long, val display: String) : MessageDTO()
 @Serializable
+@SerialName("AtAll")
+data class AtAllDTO(val target: Long = 0) : MessageDTO() // target为保留字段
+@Serializable
 @SerialName("Face")
 data class FaceDTO(val faceId: Int) : MessageDTO()
 @Serializable
@@ -83,6 +86,7 @@ fun MessageChainDTO.toMessageChain() =
 @UseExperimental(ExperimentalUnsignedTypes::class)
 fun Message.toDTO() = when (this) {
     is At -> AtDTO(target, display)
+    is AtAll -> AtAllDTO(0L)
     is Face -> FaceDTO(id.value.toInt())
     is PlainText -> PlainDTO(stringValue)
     is Image -> ImageDTO(imageId)
@@ -93,6 +97,7 @@ fun Message.toDTO() = when (this) {
 @UseExperimental(ExperimentalUnsignedTypes::class, MiraiInternalAPI::class)
 fun MessageDTO.toMessage() = when (this) {
     is AtDTO -> At(target, display)
+    is AtAllDTO -> AtAll
     is FaceDTO -> Face(FaceId(faceId.toUByte()))
     is PlainDTO -> PlainText(text)
     is ImageDTO -> Image(imageId)

mirai-api-http/src/main/kotlin/net/mamoe/mirai/api/http/util/Json.kt

@@ -51,6 +51,7 @@ object MiraiJson {
         }
         polymorphic(MessageDTO.serializer()) {
             AtDTO::class with AtDTO.serializer()
+            AtAllDTO::class with AtAllDTO.serializer()
             FaceDTO::class with FaceDTO.serializer()
             PlainDTO::class with PlainDTO.serializer()
             ImageDTO::class with ImageDTO.serializer()