英文:
Receive big file via http
问题
我正在为你翻译以下内容：
我试图通过HTTP接收一个大约25MB的文件。我通过PHP和cURL将文件发送给"golang"，然后尝试从"golang"接收它。
以下是代码：
package main
import (
"fmt"
"net/http"
"io/ioutil"
)
func handler(w http.ResponseWriter, r *http.Request) {
buf, _ := ioutil.ReadAll(r.Body)
fmt.Println(string(buf[:]))
}
func main() {
http.HandleFunc("/", handler)
http.ListenAndServe(":12100", nil)
}
在这种情况下，我可以在ioutil.ReadAll的输出中看到我的文件。但是，如果我只尝试获取文件内容，就会失败 
package main
import (
"fmt"
"net/http"
"io/ioutil"
)
func handler(w http.ResponseWriter, r *http.Request) {
r.ParseMultipartForm(0)
fmt.Println(r.FormValue("f"))
}
func main() {
http.HandleFunc("/", handler)
http.ListenAndServe(":12100", nil)
}
然而，如果文件很小（约900KB），一切都正常。通过HTTP发送大文件的正确方法是什么？
英文:
I've trying to receive big (~25Mb) file via http. From "client" i've send this file via PHP and cUrl and trying to receive it from golang.
Here is code:
package main
import (
"fmt"
"net/http"
"io/ioutil"
)
func handler(w http.ResponseWriter, r *http.Request) {
buf, _ := ioutil.ReadAll(r.Body)
fmt.Println(string(buf[:]))
}
func main() {
http.HandleFunc("/", handler)
http.ListenAndServe(":12100", nil)
}
In this case i can see my file in ioutil.ReadAll output. But if i trying to get only file contents, it is failed
package main
import (
"fmt"
"net/http"
"io/ioutil"
)
func handler(w http.ResponseWriter, r *http.Request) {
r.ParseMultipartForm(0)
fmt.Println(r.FormValue("f"))
}
func main() {
http.HandleFunc("/", handler)
http.ListenAndServe(":12100", nil)
}
However file is small (~900Kb) everything is ok. What is right way to send big files via http?
答案1
得分: 3
Go将开始将大文件写入磁盘，以防止它们堵塞内存。然后，您可以使用FormFile获取磁盘上文件的句柄。完成后，应关闭句柄并使用r.MultipartForm.RemoveAll()删除临时文件。
完整代码如下：
func handler(w http.ResponseWriter, r *http.Request) {
r.ParseMultipartForm(0)
defer r.MultipartForm.RemoveAll()
fi, info, err := r.FormFile("f")
defer fi.Close()
fmt.Printf("接收到文件：%v", info.Filename)
// 对文件进行操作
}
英文:
Go will start writing large files to disk, so that they don't clog up memory.
You can then use FormFile to get the a handle to the file on disk. When you are done you should close the handle and delete the temporary file with r.MultipartForm.RemoveAll().
All together:
func handler(w http.ResponseWriter, r *http.Request) {
r.ParseMultipartForm(0)
defer r.MultipartForm.RemoveAll()
fi, info, err := r.FormFile("f")
defer fi.Close()
fmt.Printf("Recieved %v",info.Filename)
//Do whatever with it
}
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