lure-updater/internal/builtins/http.go

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/*
* LURE Updater - Automated updater bot for LURE packages
* Copyright (C) 2023 Elara Musayelyan
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
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package builtins
import (
"bytes"
"errors"
"fmt"
"io"
"net/http"
"strings"
"go.elara.ws/logger/log"
"go.elara.ws/lure-updater/internal/config"
"go.starlark.net/starlark"
"go.starlark.net/starlarkstruct"
"golang.org/x/crypto/bcrypt"
)
const maxBodySize = 16384
var (
ErrInvalidBodyType = errors.New("invalid body type")
ErrInvalidHdrKeyType = errors.New("invalid header key type")
ErrInvalidHdrVal = errors.New("invalid header value type")
ErrInvalidType = errors.New("invalid type")
ErrInsecureWebhook = errors.New("secure webhook missing authorization")
ErrIncorrectPassword = errors.New("incorrect password")
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)
var httpModule = &starlarkstruct.Module{
Name: "http",
Members: starlark.StringDict{
"get": starlark.NewBuiltin("http.get", httpGet),
"post": starlark.NewBuiltin("http.post", httpPost),
"put": starlark.NewBuiltin("http.put", httpPut),
"head": starlark.NewBuiltin("http.head", httpHead),
},
}
func httpGet(thread *starlark.Thread, b *starlark.Builtin, args starlark.Tuple, kwargs []starlark.Tuple) (starlark.Value, error) {
return makeRequest("http.get", http.MethodGet, args, kwargs, thread)
}
func httpPost(thread *starlark.Thread, b *starlark.Builtin, args starlark.Tuple, kwargs []starlark.Tuple) (starlark.Value, error) {
return makeRequest("http.post", http.MethodPost, args, kwargs, thread)
}
func httpPut(thread *starlark.Thread, b *starlark.Builtin, args starlark.Tuple, kwargs []starlark.Tuple) (starlark.Value, error) {
return makeRequest("http.put", http.MethodPut, args, kwargs, thread)
}
func httpHead(thread *starlark.Thread, b *starlark.Builtin, args starlark.Tuple, kwargs []starlark.Tuple) (starlark.Value, error) {
return makeRequest("http.head", http.MethodHead, args, kwargs, thread)
}
type starlarkBodyReader struct {
io.Reader
}
func (sbr *starlarkBodyReader) Unpack(v starlark.Value) error {
switch v := v.(type) {
case starlark.String:
sbr.Reader = strings.NewReader(string(v))
case starlark.Bytes:
sbr.Reader = strings.NewReader(string(v))
default:
return fmt.Errorf("%w: %s", ErrInvalidBodyType, v.Type())
}
return nil
}
func newBodyReader() *starlarkBodyReader {
return &starlarkBodyReader{
Reader: bytes.NewReader(nil),
}
}
type starlarkHeaders struct {
http.Header
}
func (sh *starlarkHeaders) Unpack(v starlark.Value) error {
dict, ok := v.(*starlark.Dict)
if !ok {
return fmt.Errorf("%w: %s", ErrInvalidType, v.Type())
}
sh.Header = make(http.Header, dict.Len())
for _, key := range dict.Keys() {
keyStr, ok := key.(starlark.String)
if !ok {
return fmt.Errorf("%w: %s", ErrInvalidHdrKeyType, key.Type())
}
val, _, _ := dict.Get(key)
list, ok := val.(*starlark.List)
if !ok {
return fmt.Errorf("%w: %s", ErrInvalidHdrVal, val.Type())
}
hdrVals := make([]string, list.Len())
for i := 0; i < list.Len(); i++ {
hdrVal, ok := list.Index(i).(starlark.String)
if !ok {
return fmt.Errorf("%w: %s", ErrInvalidHdrVal, list.Index(i).Type())
}
hdrVals[i] = string(hdrVal)
}
sh.Header[string(keyStr)] = hdrVals
}
return nil
}
func makeRequest(name, method string, args starlark.Tuple, kwargs []starlark.Tuple, thread *starlark.Thread) (starlark.Value, error) {
var (
url string
redirect = true
headers = &starlarkHeaders{}
body = newBodyReader()
)
err := starlark.UnpackArgs(name, args, kwargs, "url", &url, "redirect??", &redirect, "headers??", headers, "body??", body)
if err != nil {
return nil, err
}
req, err := http.NewRequest(method, url, body)
if err != nil {
return nil, err
}
req.Header = headers.Header
client := http.DefaultClient
if !redirect {
client = &http.Client{
CheckRedirect: func(req *http.Request, via []*http.Request) error {
return http.ErrUseLastResponse
},
}
}
log.Debug("Making HTTP request").Str("url", url).Str("method", req.Method).Bool("redirect", redirect).Stringer("pos", thread.CallFrame(1).Pos).Send()
res, err := client.Do(req)
if err != nil {
return nil, err
}
log.Debug("Got HTTP response").Str("host", res.Request.URL.Host).Int("code", res.StatusCode).Stringer("pos", thread.CallFrame(1).Pos).Send()
return starlarkResponse(res), nil
}
func starlarkResponse(res *http.Response) *starlarkstruct.Struct {
return starlarkstruct.FromStringDict(starlarkstruct.Default, starlark.StringDict{
"code": starlark.MakeInt(res.StatusCode),
"headers": starlarkStringSliceMap(res.Header),
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"body": newStarlarkReader(res.Body),
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})
}
func starlarkRequest(req *http.Request) *starlarkstruct.Struct {
return starlarkstruct.FromStringDict(starlarkstruct.Default, starlark.StringDict{
"method": starlark.String(req.Method),
"remote_addr": starlark.String(req.RemoteAddr),
"headers": starlarkStringSliceMap(req.Header),
"query": starlarkStringSliceMap(req.URL.Query()),
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"body": newStarlarkReader(req.Body),
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})
}
func starlarkStringSliceMap(ssm map[string][]string) *starlark.Dict {
dict := starlark.NewDict(len(ssm))
for key, vals := range ssm {
sVals := make([]starlark.Value, len(vals))
for i, val := range vals {
sVals[i] = starlark.String(val)
}
dict.SetKey(starlark.String(key), starlark.NewList(sVals))
}
return dict
}
func registerWebhook(mux *http.ServeMux, cfg *config.Config, pluginName string) *starlark.Builtin {
return starlark.NewBuiltin("register_webhook", func(thread *starlark.Thread, b *starlark.Builtin, args starlark.Tuple, kwargs []starlark.Tuple) (starlark.Value, error) {
var fn *starlark.Function
secure := true
err := starlark.UnpackArgs("register_webhook", args, kwargs, "function", &fn, "secure??", &secure)
if err != nil {
return nil, err
}
if !secure {
log.Warn("Plugin is registering an insecure webhook").Str("plugin", pluginName).Send()
}
path := "/webhook/" + pluginName + "/" + fn.Name()
mux.HandleFunc(path, webhookHandler(pluginName, secure, cfg, thread, fn))
log.Debug("Registered webhook").Str("path", path).Str("function", fn.Name()).Stringer("pos", thread.CallFrame(1).Pos).Send()
return starlark.None, nil
})
}
func webhookHandler(pluginName string, secure bool, cfg *config.Config, thread *starlark.Thread, fn *starlark.Function) http.HandlerFunc {
return func(res http.ResponseWriter, req *http.Request) {
defer req.Body.Close()
res.Header().Add("X-Updater-Plugin", pluginName)
if secure {
err := verifySecure(cfg.Webhook.PasswordHash, pluginName, req)
if err != nil {
log.Error("Error verifying webhook").Err(err).Send()
res.WriteHeader(http.StatusForbidden)
_, _ = io.WriteString(res, err.Error())
return
}
}
log.Debug("Calling webhook function").Str("name", fn.Name()).Stringer("pos", fn.Position()).Send()
val, err := starlark.Call(thread, fn, starlark.Tuple{starlarkRequest(req)}, nil)
if err != nil {
log.Error("Error while executing webhook").Err(err).Stringer("pos", fn.Position()).Send()
res.WriteHeader(http.StatusInternalServerError)
_, _ = io.WriteString(res, err.Error())
return
}
switch val := val.(type) {
case starlark.NoneType:
res.WriteHeader(http.StatusOK)
case starlark.Int:
var code int
err = starlark.AsInt(val, &code)
if err == nil {
res.WriteHeader(code)
} else {
res.WriteHeader(http.StatusOK)
}
case starlark.String, starlark.Bytes:
body := newBodyReader()
err = body.Unpack(val)
if err != nil {
log.Error("Error unpacking returned body").Err(err).Send()
return
}
_, err = io.Copy(res, body)
if err != nil {
log.Error("Error writing body").Err(err).Send()
return
}
case *starlark.Dict:
code := http.StatusOK
codeVal, ok, _ := val.Get(starlark.String("code"))
if ok {
err = starlark.AsInt(codeVal, &code)
if err != nil {
log.Error("Error decoding returned status code").Err(err).Send()
return
}
res.WriteHeader(code)
}
body := newBodyReader()
bodyVal, ok, _ := val.Get(starlark.String("body"))
if ok {
err = body.Unpack(bodyVal)
if err != nil {
log.Error("Error unpacking returned body").Err(err).Send()
return
}
_, err = io.Copy(res, body)
if err != nil {
log.Error("Error writing body").Err(err).Send()
return
}
}
}
}
}
func verifySecure(pwdHash, pluginName string, req *http.Request) error {
var pwd []byte
if _, pwdStr, ok := req.BasicAuth(); ok {
pwdStr = strings.TrimSpace(pwdStr)
pwd = []byte(pwdStr)
} else if hdrStr := req.Header.Get("Authorization"); hdrStr != "" {
hdrStr = strings.TrimPrefix(hdrStr, "Bearer")
hdrStr = strings.TrimSpace(hdrStr)
pwd = []byte(hdrStr)
} else {
log.Warn("Insecure webhook request").
Str("from", req.RemoteAddr).
Str("plugin", pluginName).
Send()
return ErrInsecureWebhook
}
if err := bcrypt.CompareHashAndPassword([]byte(pwdHash), pwd); err != nil {
return ErrIncorrectPassword
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}
return nil
}