listmonk/utils.go

284 lines
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Go
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2018-10-25 15:51:47 +02:00
package main
import (
"bytes"
"crypto/rand"
"fmt"
"io"
"io/ioutil"
"net/http"
"os"
"path/filepath"
"reflect"
"regexp"
"strconv"
"strings"
"github.com/jmoiron/sqlx"
"github.com/knadh/goyesql"
"github.com/labstack/echo"
"github.com/lib/pq"
)
const tmpFilePrefix = "listmonk"
var (
// This matches filenames, sans extensions, of the format
// filename_(number). The number is incremented in case
// new file uploads conflict with existing filenames
// on the filesystem.
fnameRegexp, _ = regexp.Compile(`(.+?)_([0-9]+)$`)
// This replaces all special characters
tagRegexp, _ = regexp.Compile(`[^a-z0-9\-\s]`)
tagRegexpSpaces, _ = regexp.Compile(`[\s]+`)
)
// ScanToStruct prepares a given set of Queries and assigns the resulting
// *sql.Stmt statements to the fields of a given struct, matching based on the name
// in the `query` tag in the struct field names.
func scanQueriesToStruct(obj interface{}, q goyesql.Queries, db *sqlx.DB) error {
ob := reflect.ValueOf(obj)
if ob.Kind() == reflect.Ptr {
ob = ob.Elem()
}
if ob.Kind() != reflect.Struct {
return fmt.Errorf("Failed to apply SQL statements to struct. Non struct type: %T", ob)
}
// Go through every field in the struct and look for it in the Args map.
for i := 0; i < ob.NumField(); i++ {
f := ob.Field(i)
if f.IsValid() {
if tag := ob.Type().Field(i).Tag.Get("query"); tag != "" && tag != "-" {
// Extract the value of the `query` tag.
var (
tg = strings.Split(tag, ",")
name string
)
if len(tg) == 2 {
if tg[0] != "-" && tg[0] != "" {
name = tg[0]
}
} else {
name = tg[0]
}
// Query name found in the field tag is not in the map.
if _, ok := q[name]; !ok {
return fmt.Errorf("query '%s' not found in query map", name)
}
if !f.CanSet() {
return fmt.Errorf("query field '%s' is unexported", ob.Type().Field(i).Name)
}
switch f.Type().String() {
case "string":
// Unprepared SQL query.
f.Set(reflect.ValueOf(q[name].Query))
case "*sqlx.Stmt":
// Prepared query.
stmt, err := db.Preparex(q[name].Query)
if err != nil {
return fmt.Errorf("Error preparing query '%s': %v", name, err)
}
f.Set(reflect.ValueOf(stmt))
}
}
}
}
return nil
}
// uploadFile is a helper function on top of echo.Context for processing file uploads.
// It allows copying a single file given the incoming file field name.
// If the upload directory dir is empty, the file is copied to the system's temp directory.
// If name is empty, the incoming file's name along with a small random hash is used.
// When a slice of MIME types is given, the uploaded file's MIME type is validated against the list.
func uploadFile(key string, dir, name string, mimes []string, c echo.Context) (string, error) {
file, err := c.FormFile(key)
if err != nil {
return "", echo.NewHTTPError(http.StatusBadRequest,
fmt.Sprintf("Invalid file uploaded: %v", err))
}
// Check MIME type.
if len(mimes) > 0 {
var (
typ = file.Header.Get("Content-type")
ok = false
)
for _, m := range mimes {
if typ == m {
ok = true
break
}
}
if !ok {
return "", echo.NewHTTPError(http.StatusBadRequest,
fmt.Sprintf("Unsupported file type (%s) uploaded.", typ))
}
}
src, err := file.Open()
if err != nil {
return "", err
}
defer src.Close()
// There's no upload directory. Use a tempfile.
var out *os.File
if dir == "" {
o, err := ioutil.TempFile("", tmpFilePrefix)
if err != nil {
return "", echo.NewHTTPError(http.StatusInternalServerError,
fmt.Sprintf("Error copying uploaded file: %v", err))
}
out = o
name = o.Name()
} else {
// There's no explicit name. Use the one posted in the HTTP request.
if name == "" {
name = strings.TrimSpace(file.Filename)
if name == "" {
name, _ = generateRandomString(10)
}
}
name = assertUniqueFilename(dir, name)
o, err := os.OpenFile(filepath.Join(dir, name), os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0664)
if err != nil {
return "", echo.NewHTTPError(http.StatusInternalServerError,
fmt.Sprintf("Error copying uploaded file: %v", err))
}
out = o
}
defer out.Close()
if _, err = io.Copy(out, src); err != nil {
return "", echo.NewHTTPError(http.StatusInternalServerError,
fmt.Sprintf("Error copying uploaded file: %v", err))
}
return name, nil
}
// Given an error, pqErrMsg will try to return pq error details
// if it's a pq error.
func pqErrMsg(err error) string {
if err, ok := err.(*pq.Error); ok {
if err.Detail != "" {
return fmt.Sprintf("%s. %s", err, err.Detail)
}
}
return err.Error()
}
// generateRandomString generates a cryptographically random, alphanumeric string of length n.
func generateRandomString(n int) (string, error) {
const dictionary = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
var bytes = make([]byte, n)
if _, err := rand.Read(bytes); err != nil {
return "", err
}
for k, v := range bytes {
bytes[k] = dictionary[v%byte(len(dictionary))]
}
return string(bytes), nil
}
// assertUniqueFilename takes a file path and check if it exists on the disk. If it doesn't,
// it returns the same name and if it does, it adds a small random hash to the filename
// and returns that.
func assertUniqueFilename(dir, fileName string) string {
var (
ext = filepath.Ext(fileName)
base = fileName[0 : len(fileName)-len(ext)]
num = 0
)
for {
// There's no name conflict.
if _, err := os.Stat(filepath.Join(dir, fileName)); os.IsNotExist(err) {
return fileName
}
// Does the name match the _(num) syntax?
r := fnameRegexp.FindAllStringSubmatch(fileName, -1)
if len(r) == 1 && len(r[0]) == 3 {
num, _ = strconv.Atoi(r[0][2])
}
num++
fileName = fmt.Sprintf("%s_%d%s", base, num, ext)
}
}
// normalizeTags takes a list of string tags and normalizes them by
// lowercasing and removing all special characters except for dashes.
func normalizeTags(tags []string) []string {
var (
out []string
space = []byte(" ")
dash = []byte("-")
)
for _, t := range tags {
rep := bytes.TrimSpace(tagRegexp.ReplaceAll(bytes.ToLower([]byte(t)), space))
rep = tagRegexpSpaces.ReplaceAll(rep, dash)
if len(rep) > 0 {
out = append(out, string(rep))
}
}
return out
}
// makeErrorTpl takes error details and returns an errorTpl
// with the error details applied to be rendered in an HTML view.
func makeErrorTpl(pageTitle, heading, desc string) errorTpl {
if heading == "" {
heading = pageTitle
}
err := errorTpl{}
err.Title = pageTitle
err.ErrorTitle = heading
err.ErrorMessage = desc
return err
}
// parseStringIDs takes a slice of numeric string IDs and
// parses each number into an int64 and returns a slice of the
// resultant values.
func parseStringIDs(s []string) ([]int64, error) {
var vals []int64
for _, v := range s {
i, err := strconv.ParseInt(v, 10, 64)
if err != nil {
return nil, err
}
if i < 1 {
return nil, fmt.Errorf("%d is not a valid ID", i)
}
vals = append(vals, i)
}
return vals, nil
}