More app code migration (#5170)

* Migrate admin functions into app package

* More user function refactoring

* Move post functions into app package

app/saml.go

@@ -0,0 +1,67 @@
+// Copyright (c) 2017 Mattermost, Inc. All Rights Reserved.
+// See License.txt for license information.
+
+package app
+
+import (
+	"io"
+	"mime/multipart"
+	"net/http"
+	"os"
+
+	"github.com/mattermost/platform/einterfaces"
+	"github.com/mattermost/platform/model"
+	"github.com/mattermost/platform/utils"
+)
+
+func GetSamlMetadata() (string, *model.AppError) {
+	samlInterface := einterfaces.GetSamlInterface()
+
+	if samlInterface == nil {
+		err := model.NewLocAppError("GetSamlMetadata", "api.admin.saml.not_available.app_error", nil, "")
+		err.StatusCode = http.StatusNotImplemented
+		return "", err
+	}
+
+	if result, err := samlInterface.GetMetadata(); err != nil {
+		return "", model.NewLocAppError("GetSamlMetadata", "api.admin.saml.metadata.app_error", nil, "err="+err.Message)
+	} else {
+		return result, nil
+	}
+}
+
+func AddSamlCertificate(fileData *multipart.FileHeader) *model.AppError {
+	file, err := fileData.Open()
+	defer file.Close()
+	if err != nil {
+		return model.NewLocAppError("AddSamlCertificate", "api.admin.add_certificate.open.app_error", nil, err.Error())
+	}
+
+	out, err := os.Create(utils.FindDir("config") + fileData.Filename)
+	if err != nil {
+		return model.NewLocAppError("AddSamlCertificate", "api.admin.add_certificate.saving.app_error", nil, err.Error())
+	}
+	defer out.Close()
+
+	io.Copy(out, file)
+	return nil
+}
+
+func RemoveSamlCertificate(filename string) *model.AppError {
+	if err := os.Remove(utils.FindConfigFile(filename)); err != nil {
+		return model.NewLocAppError("removeCertificate", "api.admin.remove_certificate.delete.app_error",
+			map[string]interface{}{"Filename": filename}, err.Error())
+	}
+
+	return nil
+}
+
+func GetSamlCertificateStatus() map[string]interface{} {
+	status := make(map[string]interface{})
+
+	status["IdpCertificateFile"] = utils.FileExistsInConfigFolder(*utils.Cfg.SamlSettings.IdpCertificateFile)
+	status["PrivateKeyFile"] = utils.FileExistsInConfigFolder(*utils.Cfg.SamlSettings.PrivateKeyFile)
+	status["PublicCertificateFile"] = utils.FileExistsInConfigFolder(*utils.Cfg.SamlSettings.PublicCertificateFile)
+
+	return status
+}