National ID OCR API for Go: Raw HTTP for Maximum Control

package main

import (
	"bytes"
	"encoding/base64"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"os"
)

// 💰 Save 30%+ vs competitors. Get 200 free requests instantly:
// 👉 https://structocr.com/register

// --- Struct Definitions ---
type ApiResponse struct {
	Success bool           `json:"success"`
	Data    NationalIdData `json:"data"`
	Error   string         `json:"error,omitempty"`
}

type NationalIdData struct {
	CountryCode    string `json:"country_code"`
	DocumentNumber string `json:"document_number"`
	PersonalNumber string `json:"personal_number"` // e.g., CNP, CPF, NIN
	CardSeries     string `json:"card_series"`
	Surname        string `json:"surname"`
	GivenNames     string `json:"given_names"`
	Sex            string `json:"sex"`
	DateOfBirth    string `json:"date_of_birth"`
	Address        string `json:"address"`
	DateOfExpiry   string `json:"date_of_expiry"`
}

func main() {
	apiURL := "https://api.structocr.com/v1/national-id"
	apiKey := "YOUR_API_KEY_HERE"
	imagePath := "id_card.jpg" // Supports JPG, PNG, WebP

	// 1. Read Image
	imageBytes, err := os.ReadFile(imagePath)
	if err != nil {
		fmt.Printf("Error reading file: %v\n", err)
		return
	}

	// 2. Encode to Base64
	base64Image := base64.StdEncoding.EncodeToString(imageBytes)

	// 3. Prepare Payload
	payload, _ := json.Marshal(map[string]string{"img": base64Image})

	// 4. Create Request
	req, err := http.NewRequest("POST", apiURL, bytes.NewBuffer(payload))
	if err != nil {
		fmt.Printf("Request creation failed: %v\n", err)
		return
	}

	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("x-api-key", apiKey) // Required Header

	// 5. Execute Request
	client := &http.Client{}
	resp, err := client.Do(req)
	if err != nil {
		fmt.Printf("Network error: %v\n", err)
		return
	}
	defer resp.Body.Close()

	// 6. Parse Response
	body, _ := io.ReadAll(resp.Body)

	if resp.StatusCode != http.StatusOK {
		fmt.Printf("API Error (%d): %s\n", resp.StatusCode, string(body))
		return
	}

	var result ApiResponse
	if err := json.Unmarshal(body, &result); err != nil {
		fmt.Printf("JSON Parse Error: %v\n", err)
		return
	}

	if result.Success {
		data := result.Data
		fmt.Println("✅ National ID Extracted!")
		fmt.Printf("Country:    %s\n", data.CountryCode)
		fmt.Printf("Name:       %s %s\n", data.GivenNames, data.Surname)
		fmt.Printf("Doc Number: %s (Series: %s)\n", data.DocumentNumber, data.CardSeries)
		fmt.Printf("Personal #: %s\n", data.PersonalNumber)
		fmt.Printf("Address:    %s\n", data.Address)
	} else {
		fmt.Printf("Extraction failed: %s\n", result.Error)
	}
}