firehol/netdata

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

package web

import (
    "encoding/base64"
    "fmt"
    "io"
    "net/http"
    "net/url"
    "strings"

    "github.com/netdata/netdata/go/plugins/pkg/buildinfo"
    "github.com/netdata/netdata/go/plugins/pkg/executable"
)

// RequestConfig is the configuration of the HTTP request.
// This structure is not intended to be used directly as part of a module's configuration.
// Supported configuration file formats: YAML.
type RequestConfig struct {
    // URL specifies the URL to access.
    URL string `yaml:"url" json:"url"`

    // Username specifies the username for basic HTTPConfig authentication.
    Username string `yaml:"username,omitempty" json:"username"`

    // Password specifies the password for basic HTTPConfig authentication.
    Password string `yaml:"password,omitempty" json:"password"`

    // ProxyUsername specifies the username for basic HTTPConfig authentication.
    // It is used to authenticate a user agent to a proxy server.
    ProxyUsername string `yaml:"proxy_username,omitempty" json:"proxy_username"`

    // ProxyPassword specifies the password for basic HTTPConfig authentication.
    // It is used to authenticate a user agent to a proxy server.
    ProxyPassword string `yaml:"proxy_password,omitempty" json:"proxy_password"`

    // Method specifies the HTTPConfig method (GET, POST, PUT, etc.). An empty string means GET.
    Method string `yaml:"method,omitempty" json:"method"`

    // Headers specifies the HTTP request header fields to be sent by the client.
    Headers map[string]string `yaml:"headers,omitempty" json:"headers"`

    // Body specifies the HTTP request body to be sent by the client.
    Body string `yaml:"body,omitempty" json:"body"`
}

// Copy makes a full copy of the RequestConfig.
func (r RequestConfig) Copy() RequestConfig {
    headers := make(map[string]string, len(r.Headers))
    for k, v := range r.Headers {
        headers[k] = v
    }
    r.Headers = headers
    return r
}

var userAgent = fmt.Sprintf("Netdata %s.plugin/%s", executable.Name, buildinfo.Version)

// NewHTTPRequest returns a new *http.Requests given a RequestConfig configuration and an error if any.
func NewHTTPRequest(cfg RequestConfig) (*http.Request, error) {
    var body io.Reader
    if cfg.Body != "" {
        body = strings.NewReader(cfg.Body)
    }

    req, err := http.NewRequest(cfg.Method, cfg.URL, body)
    if err != nil {
        return nil, err
    }

    req.Header.Set("User-Agent", userAgent)

    if cfg.Username != "" || cfg.Password != "" {
        req.SetBasicAuth(cfg.Username, cfg.Password)
    }

    if cfg.ProxyUsername != "" && cfg.ProxyPassword != "" {
        basicAuth := base64.StdEncoding.EncodeToString([]byte(cfg.ProxyUsername + ":" + cfg.ProxyPassword))
        req.Header.Set("Proxy-Authorization", "Basic "+basicAuth)
    }

    for k, v := range cfg.Headers {
        switch k {
        case "host", "Host":
            req.Host = v
        default:
            req.Header.Set(k, v)
        }
    }

    return req, nil
}

func NewHTTPRequestWithPath(cfg RequestConfig, urlPath string) (*http.Request, error) {
    cfg = cfg.Copy()

    v, err := url.JoinPath(cfg.URL, urlPath)
    if err != nil {
        return nil, fmt.Errorf("failed to join URL path: %v", err)
    }
    cfg.URL = v

    return NewHTTPRequest(cfg)
}