Go HTML to PDF API

package main

import (
    "context"
    "encoding/json"
    "errors"
    "fmt"
    "net/http"
    "net/url"
    "time"
)

var client = &http.Client{Timeout: 60 * time.Second}

func pdfURL(ctx context.Context, target string) (string, error) {
    endpoint, err := url.Parse("https://api.microlink.io")
    if err != nil {
        return "", err
    }

    query := endpoint.Query()
    query.Set("url", target)
    query.Set("pdf", "true")
    query.Set("meta", "false")
    endpoint.RawQuery = query.Encode()

    req, err := http.NewRequestWithContext(ctx, http.MethodGet, endpoint.String(), nil)
    if err != nil {
        return "", err
    }

    res, err := client.Do(req)
    if err != nil {
        return "", err
    }
    defer res.Body.Close()

    var payload struct {
        Message string `json:"message"`
        Data    struct {
            PDF struct {
                URL string `json:"url"`
            } `json:"pdf"`
        } `json:"data"`
    }

    if err := json.NewDecoder(res.Body).Decode(&payload); err != nil {
        return "", fmt.Errorf("microlink: %s: %w", res.Status, err)
    }

    if res.StatusCode != http.StatusOK {
        return "", fmt.Errorf("microlink: %s: %s", res.Status, payload.Message)
    }

    if payload.Data.PDF.URL == "" {
        return "", errors.New("microlink: no pdf url in response")
    }

    return payload.Data.PDF.URL, nil
}

func main() {
    link, err := pdfURL(context.Background(), "https://example.com")
    if err != nil {
        panic(err)
    }

    fmt.Println(link)
}

func setOptions(query url.Values, target string) {
    query.Set("url", target)
    query.Set("pdf.format", "A4")        // A0-A6 | Letter | Legal | Tabloid
    query.Set("pdf.margin", "0.35cm")    // cm, mm, in or px
    query.Set("pdf.landscape", "false")  // portrait (default) | landscape
    query.Set("pdf.scale", "1")          // zoom the rendering, 0.1 to 2
    query.Set("mediaType", "print")      // print CSS stylesheets | screen (default)
    query.Set("meta", "false")
}