change SMS max length (#1295)

Author: mikehelmick

cmd/server/assets/realmadmin/_form_codes.html

@@ -203,7 +203,13 @@
       The SMS message will be constructed based on the template you provide. The overall
       length of of the SMS message should not exceed 160 characters, or your message will need to be split
       in transit and may not be joined correctly. There are some special strings that you can use
-      to substitute items.
+      to substitute items.<br/>
+      
+      If your choose to exceed 160 characters, your message will be broken up into
+      individual messages of 153 characters and reconstructed at the mobile device.  The user may be
+      charged for each individual message. The overall maximum length of an SMS Template is {{.maxSMSTemplate}}
+      characters before expansion.
+      <br/>
       {{if $realm.EnableENExpress}}
         Your SMS template <em>MUST</em> contain <code>[enslink]</code>.
         <ul>

pkg/controller/realmadmin/settings.go

@@ -452,6 +452,8 @@ func (c *Controller) renderSettings(
 	m["longCodeHours"] = longCodeHours
 	m["enxRedirectDomain"] = c.config.GetENXRedirectDomain()
 
+	m["maxSMSTemplate"] = database.SMSTemplateMaxLength
+
 	m["quotaLimit"] = quotaLimit
 	m["quotaRemaining"] = quotaRemaining
 

pkg/database/migrations.go

@@ -1736,6 +1736,17 @@ func (db *Database) getMigrations(ctx context.Context) *gormigrate.Gormigrate {
 				return tx.Exec(sql).Error
 			},
 		},
+		{
+			ID: "00072-ChangeSMSTemplateType",
+			Migrate: func(tx *gorm.DB) error {
+				logger.Debugw("changing type of SMS Template text")
+				return tx.Exec("ALTER TABLE realms ALTER COLUMN sms_text_template TYPE text").Error
+			},
+			Rollback: func(tx *gorm.DB) error {
+				// No rollback for this, as there is no reason to do so.
+				return nil
+			},
+		},
 	})
 }
 

pkg/database/realm.go

@@ -20,6 +20,7 @@ import (
 	"fmt"
 	"math"
 	"net"
+	"os"
 	"sort"
 	"strings"
 	"time"
@@ -81,6 +82,9 @@ const (
 	SMSLongExpires   = "[longexpires]"
 	SMSENExpressLink = "[enslink]"
 
+	SMSTemplateMaxLength    = 800
+	SMSTemplateExpansionMax = 918
+
 	EmailInviteLink        = "[invitelink]"
 	EmailPasswordResetLink = "[passwordresetlink]"
 	EmailVerifyLink        = "[verifylink]"
@@ -136,7 +140,7 @@ type Realm struct {
 	LongCodeDuration DurationSeconds `gorm:"type:bigint; not null; default: 86400"` // default 24h
 
 	// SMS configuration
-	SMSTextTemplate string `gorm:"type:varchar(400); not null; default: 'This is your Exposure Notifications Verification code: [longcode] Expires in [longexpires] hours'"`
+	SMSTextTemplate string `gorm:"type:text; not null; default: 'This is your Exposure Notifications Verification code: [longcode] Expires in [longexpires] hours'"`
 
 	// SMSCountry is an optional field to hint the default phone picker country
 	// code.
@@ -369,6 +373,19 @@ func (r *Realm) BeforeSave(tx *gorm.DB) error {
 		}
 	}
 
+	// Check template length.
+	if l := len(r.SMSTextTemplate); l > SMSTemplateMaxLength {
+		r.AddError("SMSTextTemplate", fmt.Sprintf("must be %v characters or less, current message is %v characters long", SMSTemplateMaxLength, l))
+	}
+	// Check expansion length based on settings.
+	fakeCode := fmt.Sprintf(fmt.Sprintf("\\%0%d\\%d", r.CodeLength), 0)
+	fakeLongCode := fmt.Sprintf(fmt.Sprintf("\\%0%d\\%d", r.LongCodeLength), 0)
+	enxDomain := os.Getenv("ENX_REDIRECT_DOMAIN")
+	expandedSMSText := r.BuildSMSText(fakeCode, fakeLongCode, enxDomain)
+	if l := len(expandedSMSText); l > SMSTemplateExpansionMax {
+		r.AddError("SMSTextTemplate", fmt.Sprintf("when expanded, the result message is too long (%v characters). The max expanded message is %v characters", l, SMSTemplateExpansionMax))
+	}
+
 	if r.UseSystemEmailConfig && !r.CanUseSystemEmailConfig {
 		r.AddError("useSystemEmailConfig", "is not allowed on this realm")
 	}