如何从HTTP响应中读取附件

I am trying to download some csv data from a URL. The raw response looks something like this

HTTP/1.1 200 OK
Server: Europa-4
X-Varnish: 33948791
Vary: Accept-Encoding, X-UA-Device
X-Cache: MISS
Cache-Control: no-cache, no-cache, no-store, proxy-revalidate, must-revalidate, max-age=0
Content-Type: application/octet-stream
P3p: CP="CAO PSA OUR"
Date: Fri, 01 Sep 2017 19:53:27 GMT
X-Server: web03
Expires: Fri, 01 Sep 2017 19:53:26 GMT
X-XSS-Protection: 1; mode=block
Transfer-Encoding: chunked
Accept-Ranges: bytes
X-Content-Type-Options: nosniff
Content-Disposition: attachment; filename="GooglePLAv1US.txt"
Via: 1.1 varnish-v4
Connection: keep-alive
Last-Modified: Fri, 01 Sep 2017 19:53:27 +0000
X-Frame-Options: sameorigin
X-UA-Device: desktop
Age: 0
X-Modified-Url: /amfeed/main/get/file/GooglePLAv1US/?___store=ca_en

id      title   description     google_product_category  .....
20649074       ......
20652632       ......
.
.
.

Now I realize this is not really a multi-part response, but it has the Content-Disposition: attachment; filename="GooglePLAv1US.txt" header, which says it needs to be treated as a download by the browser.

When I try to read the body of response, it throws the error unexpected EOF. How do I read this data, it's not really in any kind of a section?

Code

http.DefaultClient.Timeout = time.Second * 30
resp, err := http.Get(ht.Creds.AccessData.URL)
if err != nil {
    return nil, err
}
defer resp.Body.Close()
d, err := ioutil.ReadAll(resp.Body)
if err != nil {
    return nil, errors.Wrap(err, "Error reading HTTP response body")
}

This produces the error

Error reading HTTP response body: unexpected EOF

Give a try to net/textproto, here is a small example:

package main

import (
    "bufio"
    "fmt"
    "io"
    "net/http"
    "net/http/httptest"
    "net/textproto"
    "os"
)

func main() {
    ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
        fmt.Fprintf(w, "%s
%s
%s
%s
",
            "col1,col2,col3",
            "1,2,3",
            "a,b,c",
            "x,y,x",
        )
    }))
    defer ts.Close()

    client := &http.Client{}
    res, err := client.Get(ts.URL)
    if err != nil {
        fmt.Fprintln(os.Stderr, err)
        return
    }
    defer res.Body.Close()
    reader := bufio.NewReader(res.Body)
    tp := textproto.NewReader(reader)
    for {
        if line, err := tp.ReadLine(); err != nil {
            if err == io.EOF {
                // if file is emtpy
                return
            }
            return
        } else {
            fmt.Printf("%s

", line)
        }
    }
}

https://play.golang.org/p/fee4B5mh35

Here is another example based on your original question regarding "csv":

package main

import (
    "bufio"
    "fmt"
    "net/http"
    "os"
)

func main() {
    client := &http.Client{}
    res, err := client.Get("http://samplecsvs.s3.amazonaws.com/Sacramentorealestatetransactions.csv")
    if err != nil {
        fmt.Fprintln(os.Stderr, err)
        return
    }
    defer res.Body.Close()
    scanner := bufio.NewScanner(res.Body)
    scanner.Split(bufio.ScanBytes)
    for scanner.Scan() {
        c := scanner.Text()
        switch c {
        case "":
            fmt.Println()
        default:
            fmt.Printf("%s", c)
        }
    }
}

In this case, notice the scanner.Split(bufio.ScanBytes), hope this can give you more ideas.