159 lines
5.1 KiB
Go
159 lines
5.1 KiB
Go
// Copyright 2022 E99p1ant. All rights reserved.
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// Use of this source code is governed by a MIT-style
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// license that can be found in the LICENSE file.
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package form
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import (
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"mime"
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"mime/multipart"
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"net/http"
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"reflect"
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"github.com/flamego/flamego"
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"github.com/flamego/template"
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"github.com/unknwon/com"
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"github.com/wuhan005/govalid"
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"github.com/tamakyi/TamaBox/internal/context"
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)
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type ErrorCategory string
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const (
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ErrorCategoryDeserialization ErrorCategory = "deserialization"
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ErrorCategoryValidation ErrorCategory = "validation"
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)
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type Error struct {
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Category ErrorCategory
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Error error
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}
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const (
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multipartMemoryLimit = 10 << 20 // 10 MiB：multipart 内存驻留上限，超出由 mime/multipart 落盘
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// MaxRequestBodySize 请求体总大小上限（含落盘部分），略高于内存上限以留出开销。
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//
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// ⚠️ 必须显式限制：ParseMultipartForm 的参数只约束内存缓冲，超出部分会无上限写入
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// 临时文件；匿名可达的提问接口即接受 multipart，无总量限制则可持续撑满磁盘。
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// 导出供 internal/route/bodylimit.go 的全局中间件复用——仅靠本 Bind 内限制不够，
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// 组级 CSRF 校验先于 Bind 执行且会整包惰性解析 body，须把上限提前到一切解析之前。
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MaxRequestBodySize = 12 << 20 // 12 MiB
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)
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func Bind(model interface{}) flamego.Handler {
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if reflect.TypeOf(model).Kind() == reflect.Ptr {
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panic("form: pointer can not be accepted as binding model")
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}
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return func(c context.Context, data template.Data) {
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obj := reflect.New(reflect.TypeOf(model))
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defer func() { c.Map(obj.Elem().Interface()) }()
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r := c.Request()
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// 在任何解析之前封顶请求体总大小。c.Request() 是 flamego 包装类型（Body 是方法
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// 而非字段），须取内嵌 *http.Request 才能替换。超限后 Read 报错，使 ParseForm /
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// ParseMultipartForm 失败并走反序列化错误分支，避免超大 body 落盘或读入内存。
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httpReq := r.Request
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httpReq.Body = http.MaxBytesReader(c.ResponseWriter(), httpReq.Body, MaxRequestBodySize)
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contentType, _, _ := mime.ParseMediaType(r.Header.Get("Content-Type"))
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switch contentType {
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case "application/x-www-form-urlencoded", "":
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if err := r.ParseForm(); err != nil {
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// ⚠️ 必须 SetError：flamego 的 handler 链只要响应未写入就会自动执行下一 handler，
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// 仅 Map(Error) 不中断链，零值结构体会照常进入业务动作（静默清空屏蔽词、解除
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// 页面密码等）。SetError 置位 HasError，action 开头的 abortOnFormError 守卫会早退。
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c.SetError(err)
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c.Map(Error{Category: ErrorCategoryDeserialization, Error: err})
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return
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}
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case "multipart/form-data":
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if err := r.ParseMultipartForm(multipartMemoryLimit); err != nil {
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c.SetError(err)
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c.Map(Error{Category: ErrorCategoryDeserialization, Error: err})
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return
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}
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}
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typ := reflect.TypeOf(obj.Interface())
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val := reflect.ValueOf(obj.Interface())
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if typ.Kind() == reflect.Ptr {
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typ = typ.Elem()
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val = val.Elem()
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}
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for i := 0; i < typ.NumField(); i++ {
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field := typ.Field(i)
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fieldName := typ.Field(i).Tag.Get("form")
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if fieldName == "" {
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fieldName = com.ToSnakeCase(field.Name)
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}
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if r.MultipartForm != nil {
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fhType := reflect.TypeOf((*multipart.FileHeader)(nil))
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value, ok := r.MultipartForm.Value[fieldName]
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if ok {
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if val.Field(i).Kind() == reflect.Slice && val.Field(i).Type().Elem() == fhType {
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continue
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}
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// FIXME: We don't implement the slice type yet.
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val.Field(i).Set(reflect.ValueOf(value[0]))
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} else {
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value, ok := r.MultipartForm.File[fieldName]
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if ok {
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numElems := len(value)
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if val.Field(i).Kind() == reflect.Slice && numElems > 0 && val.Field(i).Type().Elem() == fhType {
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slice := reflect.MakeSlice(val.Field(i).Type(), numElems, numElems)
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for i := 0; i < numElems; i++ {
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slice.Index(i).Set(reflect.ValueOf(value[i]))
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}
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val.Field(i).Set(slice)
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} else if val.Field(i).Type() == fhType {
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val.Field(i).Set(reflect.ValueOf(value[0]))
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}
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}
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}
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} else {
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// 非 multipart 请求仅绑定 string 字段，其余类型（如 []*multipart.FileHeader
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// 图片字段）保持零值，否则 reflect.Set 会因类型不匹配 panic。
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// 带 enctype 的提问表单走上面分支从未触发，纯文本提交（如私聊）会命中此路径。
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if val.Field(i).Kind() == reflect.String {
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val.Field(i).Set(reflect.ValueOf(r.Form.Get(fieldName)))
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}
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}
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}
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errors, ok := govalid.Check(obj.Interface())
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if !ok {
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Assign(obj.Interface(), data)
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c.SetError(errors[0])
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c.Map(Error{Category: ErrorCategoryValidation, Error: errors[0]})
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return
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}
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}
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}
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// Assign assigns form values back to the template data.
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func Assign(form interface{}, data map[string]interface{}) {
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typ := reflect.TypeOf(form)
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val := reflect.ValueOf(form)
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if typ.Kind() == reflect.Ptr {
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typ = typ.Elem()
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val = val.Elem()
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}
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for i := 0; i < typ.NumField(); i++ {
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field := typ.Field(i)
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fieldName := com.ToSnakeCase(field.Name)
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data[fieldName] = val.Field(i).Interface()
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}
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}
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