Mono repo -> Master (#22553)

Combines the following repositories into one:

https://github.com/mattermost/mattermost-server
https://github.com/mattermost/mattermost-webapp
https://github.com/mattermost/focalboard
https://github.com/mattermost/mattermost-plugin-playbooks

server/platform/services/docextractor/pdf.go

@@ -0,0 +1,58 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package docextractor
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"path"
+	"strings"
+
+	"github.com/ledongthuc/pdf"
+)
+
+type pdfExtractor struct{}
+
+func (pe *pdfExtractor) Match(filename string) bool {
+	supportedExtensions := map[string]bool{
+		"pdf": true,
+	}
+	extension := strings.TrimPrefix(path.Ext(filename), ".")
+	return supportedExtensions[extension]
+}
+
+func (pe *pdfExtractor) Extract(filename string, r io.ReadSeeker) (out string, outErr error) {
+	defer func() {
+		if r := recover(); r != nil {
+			out = ""
+			outErr = errors.New("error extracting pdf text")
+		}
+	}()
+	f, err := os.CreateTemp(os.TempDir(), "pdflib")
+	if err != nil {
+		return "", fmt.Errorf("error creating temporary file: %v", err)
+	}
+	defer f.Close()
+	defer os.Remove(f.Name())
+	size, err := io.Copy(f, r)
+	if err != nil {
+		return "", fmt.Errorf("error copying data into temporary file: %v", err)
+	}
+
+	reader, err := pdf.NewReader(f, size)
+	if err != nil {
+		return "", err
+	}
+
+	var buf bytes.Buffer
+	b, err := reader.GetPlainText()
+	if err != nil {
+		return "", err
+	}
+	buf.ReadFrom(b)
+	return buf.String(), nil
+}