effective storage of offset (#6)

.gitignore

@@ -39,4 +39,5 @@ test.*
 *.sublime-workspace
 .DS_Store
 /coverage/
-.nyc_output/
+.nyc_output/
+.vscode*

src/backend/model/database/enitites/MediaEntity.ts

@@ -4,6 +4,7 @@ import {MediaDimension, MediaDTO, MediaMetadata,} from '../../../../common/entit
 import {PersonJunctionTable} from './PersonJunctionTable';
 import {columnCharsetCS} from './EntityUtils';
 import {CameraMetadata, FaceRegion, GPSMetadata, PositionMetaData,} from '../../../../common/entities/PhotoDTO';
+import { Utils } from '../../../../common/Utils';
 
 export class MediaDimensionEntity implements MediaDimension {
   @Column('int')
@@ -106,7 +107,12 @@ export class MediaMetadataEntity implements MediaMetadata {
   @Index()
   creationDate: number;
   
-  @Column('text')
+  @Column('smallint', {
+    transformer: {
+      from: (v) => Utils.getOffsetString(v), //from database repr. as smallint (minutes) to string (+/-HH:MM)
+      to: (v) => Utils.getOffsetMinutes(v), //from entiry repr. as string (+/-HH:MM) to smallint (minutes)
+    },
+  })
   creationDateOffset?: string;
 
 

src/backend/model/fileaccess/MetadataLoader.ts

@@ -226,14 +226,7 @@ export class MetadataLoader {
         //offset in minutes is the difference between gps timestamp and given timestamp
         //to calculate this correctly, we have to work with the same offset
         const offsetMinutes = (timestampToMS(timestamp, '+00:00')- timestampToMS(UTCTimestamp, '+00:00')) / 1000 / 60;
-        if (-720 <= offsetMinutes && offsetMinutes <= 840) {
-          //valid offset is within -12 and +14 hrs (https://en.wikipedia.org/wiki/List_of_UTC_offsets)
-          return (offsetMinutes < 0 ? "-" : "+") +                              //leading +/-
-            ("0" + Math.trunc(Math.abs(offsetMinutes) / 60)).slice(-2) + ":" +  //zeropadded hours and ':'
-            ("0" + Math.abs(offsetMinutes) % 60).slice(-2);                     //zeropadded minutes
-        } else {
-          return undefined;
-        }
+        return Utils.getOffsetString(offsetMinutes);
       } else {
         return undefined;
       }

src/common/Utils.ts

@@ -124,6 +124,29 @@ export class Utils {
     return new Date(new Date(d).toISOString().substring(0,19) + (offset ? offset : '')).getFullYear();
   }
 
+  static getOffsetString(offsetMinutes: number) {
+    if (-720 <= offsetMinutes && offsetMinutes <= 840) {
+      //valid offset is within -12 and +14 hrs (https://en.wikipedia.org/wiki/List_of_UTC_offsets)
+      return (offsetMinutes < 0 ? "-" : "+") +                              //leading +/-
+        ("0" + Math.trunc(Math.abs(offsetMinutes) / 60)).slice(-2) + ":" +  //zeropadded hours and ':'
+        ("0" + Math.abs(offsetMinutes) % 60).slice(-2);                     //zeropadded minutes
+    } else {
+      return undefined;
+    }
+  }
+
+  static getOffsetMinutes(offsetString: string) { //Convert offset string (+HH:MM or -HH:MM) into a minute value
+    const regex = /^([+\-](0[0-9]|1[0-4]):[0-5][0-9])$/; //checks if offset is between -14:00 and +14:00. 
+                                                         //-12:00 is the lowest valid UTC-offset, but we allow down to -14 for efficiency
+    if (regex.test(offsetString)) {
+      let hhmm = offsetString.split(":");
+      let hours = parseInt(hhmm[0]);
+      return hours < 0 ? ((hours*60) - parseInt(hhmm[1])) : ((hours*60) + parseInt(hhmm[1]));
+    } else {
+      return undefined;
+    }
+  }
+
   static renderDataSize(size: number): string {
     const postFixes = ['B', 'KB', 'MB', 'GB', 'TB'];
     let index = 0;

src/common/entities/ConentWrapper.ts

@@ -79,6 +79,11 @@ export class ContentWrapper {
       (media as MediaDTO).metadata['t'] = (media as MediaDTO).metadata.creationDate / 1000; // skip millies
       delete (media as MediaDTO).metadata.creationDate;
 
+      if ((media as MediaDTO).metadata.creationDateOffset) {
+        // @ts-ignore
+        (media as MediaDTO).metadata['o'] = Utils.getOffsetMinutes((media as MediaDTO).metadata.creationDateOffset); // offset in minutes
+        delete (media as MediaDTO).metadata.creationDateOffset;
+      }
 
       if ((media as PhotoDTO).metadata.rating) {
         // @ts-ignore
@@ -338,6 +343,14 @@ export class ContentWrapper {
         delete (media as PhotoDTO).metadata['t'];
       }
 
+      // @ts-ignore
+      if (typeof (media as PhotoDTO).metadata['o'] !== 'undefined') {
+        // @ts-ignore
+        (media as PhotoDTO).metadata.creationDateOffset = Utils.getOffsetString((media as PhotoDTO).metadata['o']) ;//convert offset from minutes to String
+        // @ts-ignore
+        delete (media as PhotoDTO).metadata['o'];
+      }
+
       // @ts-ignore
       if (typeof (media as PhotoDTO).metadata['r'] !== 'undefined') {
         // @ts-ignore

test/TestHelper.ts

@@ -55,6 +55,7 @@ export class TestHelper {
     m.caption = null;
     m.size = sd;
     m.creationDate = 1656069387772;
+    m.creationDateOffset = "+02:00"
     m.fileSize = 123456789;
     // m.rating = 0; no rating by default
 
@@ -101,6 +102,7 @@ export class TestHelper {
     m.positionData = pd;
     m.size = sd;
     m.creationDate = 1656069387772;
+    m.creationDateOffset = "-05:00";
     m.fileSize = 123456789;
     // m.rating = 0; no rating by default
 
@@ -177,6 +179,7 @@ export class TestHelper {
     p.metadata.positionData.GPSData.latitude = 10;
     p.metadata.positionData.GPSData.longitude = 10;
     p.metadata.creationDate = 1656069387772 - 1000;
+    p.metadata.creationDateOffset = "+00:00";
     p.metadata.rating = 1;
     p.metadata.size.height = 1000;
     p.metadata.size.width = 1000;
@@ -215,6 +218,7 @@ export class TestHelper {
     p.metadata.positionData.GPSData.latitude = -10;
     p.metadata.positionData.GPSData.longitude = -10;
     p.metadata.creationDate = 1656069387772 - 2000;
+    p.metadata.creationDateOffset = "+11:00";
     p.metadata.rating = 2;
     p.metadata.size.height = 2000;
     p.metadata.size.width = 1000;
@@ -247,6 +251,7 @@ export class TestHelper {
     p.metadata.positionData.GPSData.latitude = 10;
     p.metadata.positionData.GPSData.longitude = 15;
     p.metadata.creationDate = 1656069387772 - 3000;
+    p.metadata.creationDateOffset = "-03:45";
     p.metadata.rating = 3;
     p.metadata.size.height = 1000;
     p.metadata.size.width = 2000;
@@ -275,6 +280,7 @@ export class TestHelper {
     p.metadata.positionData.GPSData.latitude = 15;
     p.metadata.positionData.GPSData.longitude = 10;
     p.metadata.creationDate = 1656069387772 - 4000;
+    p.metadata.creationDateOffset = "+04:30";
     p.metadata.size.height = 3000;
     p.metadata.size.width = 2000;
 
@@ -394,6 +400,7 @@ export class TestHelper {
       positionData: pd,
       size: sd,
       creationDate: Date.now() + ++TestHelper.creationCounter,
+      creationDateOffset: "+01:00",
       fileSize: rndInt(10000),
       caption: rndStr(),
       rating: rndInt(5) as any,