来自 csv 文件的 JSON 格式的 Golang POST 请求

Question

so I am trying to POST a csv file in JSON format to a website in Golang. I have been successful in POSTing a singular JSON file. However, that is not what I want the purpose of my program to be. Basically, I'm trying to create an account generator for a site. I want to be able to generate multiple accounts at once. I feel the best way to do this is with a csv file.

I've tried using encoding/csv to read the csv file then marshal to JSON. Also, ioutil.ReadFile() . However, the response from the site is, 'first name is mandatory field, last name is a mandatory field' etc etc. So, this obviously means the csv data is not going into JSON format. I'll show my code with the ioutil.ReadFile() below.

func main() {
file, _ := ioutil.ReadFile("accounts.csv")

    jsonConv, _ := json.Marshal(file)

    client := http.Client{}

    req, err := http.NewRequest("POST", "websiteUrlHere", bytes.NewBuffer(jsonConv))
    req.Header.Add("cookie", `"really long cookie goes here"`)
    req.Header.Set("user-agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/81.0.4044.138 Safari/537.36")
    req.Header.Set("content-type", "application/json")

    resp, err := client.Do(req)
    if err != nil {
        fmt.Print(err)
    }
    defer resp.Body.Close()
}

(^ This is just a snippet of the code).

I'm still pretty new to all of this so please understand if the question lacks anything. I've also looked for similar questions but all I find is the use of a struct. I feel this wouldn't be applicable for this as the goal is to create unlimited accounts at once.

Hope the above is sufficient. Thank you.

Answer 1

The issue with your code is actually that you're trying to convert a file to bytes with:

file, _ := ioutil.ReadFile("accounts.csv")

...and then you are AGAIN trying to convert that slice of bytes to JSON bytes with:

jsonConv, _ := json.Marshal(file)

Where the text contents of the file are stored as a slice of bytes in the variable file , and then that slice of bytes (the file contents in bytes form) is then being converted to a JSON array of bytes. So you are basically sending a JSON array of numbers...not good.

The normal flow here would be to take the file bytes and then create a Go struct(s) out of it. Once your Go objects are in place, THEN you would marshal to JSON. That converts the Go objects to a slice of bytes AFTER it has been converted to JSON text form.

So what you are missing is the Go structure middle step but you also should keep in mind that converting a Go struct to JSON bytes with json.Marshal() will only show fields that are exported. Also, usually you should use struct tags to customize exactly how the fields will show up.

Your best bet is just to stick with JSON, forget about the CSV. In your own code example, you are taking a CSV and then trying to convert it to JSON...so, then, just use JSON.

If you want to send multiple accounts, just make your Go structure a slice, which will marshal into a JSON array, which is basically what you are trying to do. The end result will be a JSON array of accounts. Here's a simple example:

package main

import (
    "fmt"
    "encoding/json"
)

type Account struct {
    Username string `json:"username"`
    Email string `json:"email"`
}

type AccountsRequest struct {
    Accounts []Account `json:"accounts"`
}

func main() {
    //gather account info
    acct1 := Account{Username: "tom", Email: "tom@example.com"}
    acct2 := Account{Username: "dick", Email: "dick@example.com"}
    acct3 := Account{Username: "harry", Email: "harry@example.com"}
    
    //create request
    acctsReq := AccountsRequest{Accounts: []Account{acct1, acct2, acct3}}
    
    //convert to JSON bytes/data
    //jsonData, _ := json.Marshal(acctsReq)
    
    //debug/output
    jsonDataPretty, _ := json.MarshalIndent(acctsReq, "", "  ")
    fmt.Println(string(jsonDataPretty))
    
    //send request with data
    //...
}

Runnable here in playground.

The key is that the structs are set up and ready to go and the struct tags determine what the JSON field names will be (ie username & email for each account and accounts for the overall array of accounts).

Hope that helps. Drop a comment if you need more specific help.

Answer 2

You need to parse the CSV file first and convert it into the list that you want:

package main


func main() {
   file, err := os.Open("file.csv")
   if err != nil {
      log.Fatal("failed opening file because: %s", err.Error())
   }
   r := csv.NewReader(file)

   records, err := r.ReadAll()
   if err != nil {
      log.Fatal(err)
   }
   fmt.Print(records)
}

The above code is parsing the list into a [][]string array. you will now need to iterate over that array and turn it into the json object that the page needs. Then you can send it. You can read more about the csv package here: https://golang.org/pkg/encoding/csv/

A word of advise: never ignore errors, they might give you useful information.