firehol/netdata

// SPDX-License-Identifier: GPL-3.0-or-later

package web

import (
    "encoding/json"
    "encoding/xml"
    "fmt"
    "io"
    "net/http"
)

type Client struct {
    httpClient *http.Client
    onNokCode  func(resp *http.Response) (bool, error)
}

func DoHTTP(cl *http.Client) *Client {
    return &Client{
        httpClient: cl,
    }
}

func (c *Client) OnNokCode(fn func(resp *http.Response) (bool, error)) *Client {
    c.onNokCode = fn
    return c
}

func (c *Client) RequestJSON(req *http.Request, in any) error {
    return c.Request(req, func(body io.Reader) error {
        return json.NewDecoder(body).Decode(in)
    })
}

func (c *Client) RequestXML(req *http.Request, in any, opts ...func(dec *xml.Decoder)) error {
    return c.Request(req, func(body io.Reader) error {
        dec := xml.NewDecoder(body)
        for _, opt := range opts {
            opt(dec)
        }
        return dec.Decode(in)
    })
}

func (c *Client) Request(req *http.Request, parse func(body io.Reader) error) error {
    resp, err := c.httpClient.Do(req)
    if err != nil {
        return fmt.Errorf("error on HTTP request to '%s': %w", req.URL, err)
    }

    defer CloseBody(resp)

    if resp.StatusCode != http.StatusOK {
        if err := c.handleNokCode(req, resp); err != nil {
            return err
        }
    }

    if parse != nil {
        if err := parse(resp.Body); err != nil {
            return fmt.Errorf("error on parsing response from '%s': %w", req.URL, err)
        }
    }

    return nil
}

func (c *Client) handleNokCode(req *http.Request, resp *http.Response) error {
    if c.onNokCode != nil {
        handled, err := c.onNokCode(resp)
        if err != nil {
            return fmt.Errorf("'%s' returned HTTP status code: %d (%w)", req.URL, resp.StatusCode, err)
        }
        if handled {
            return nil
        }
    }
    return fmt.Errorf("'%s' returned HTTP status code: %d", req.URL, resp.StatusCode)
}

func CloseBody(resp *http.Response) {
    if resp != nil && resp.Body != nil {
        _, _ = io.Copy(io.Discard, resp.Body)
        _ = resp.Body.Close()
    }
}