記一次gin PostForm bug

bug說明及分析

Gin master分支在20190602-20190612期間的版本,存在通過c.PostForm獲取form中的參數有誤的bug。
此bug在有一定併發時，由於複用之前的連接而未清除之前的緩存，導致獲取的參數爲舊參數。

type Context struct {
	...
	// formCache use url.ParseQuery cached PostForm contains the parsed form data from POST, PATCH,
	// or PUT body parameters.
	formCache url.Values
}

func (c *Context) reset() {
	c.Writer = &c.writermem
	c.Params = c.Params[0:0]
	c.handlers = nil
	c.index = -1
	c.fullPath = ""
	c.Keys = nil
	c.Errors = c.Errors[0:0]
	c.Accepted = nil
	c.queryCache = nil
	//此處未重置formCache
}

func (c *Context) getFormCache() {
	if c.formCache == nil {
		c.formCache = make(url.Values)
		req := c.Request
		if err := req.ParseMultipartForm(c.engine.MaxMultipartMemory); err != nil {
			if err != http.ErrNotMultipart {
				debugPrint("error on parse multipart form array: %v", err)
			}
		}
		c.formCache = req.PostForm
	}
}

bug修復歷史

具體修復歷史見：此處

建議

更新gin至最新即可，如果無法更新，則建議使用c.Request.PostFormValue(key)代替c.PostForm(key)