Support timezone conversions in datetimeformat filter.

src/main/java/com/hubspot/jinjava/lib/filter/DateTimeFormatFilter.java

@@ -11,7 +11,8 @@
     value = "Formats a date object",
     params = {
         @JinjavaParam(value = "value", defaultValue = "current time", desc = "The date variable or UNIX timestamp to format"),
-        @JinjavaParam(value = "format", defaultValue = StrftimeFormatter.DEFAULT_DATE_FORMAT, desc = "The format of the date determined by the directives added to this parameter")
+        @JinjavaParam(value = "format", defaultValue = StrftimeFormatter.DEFAULT_DATE_FORMAT, desc = "The format of the date determined by the directives added to this parameter"),
+        @JinjavaParam(value = "timezone", defaultValue = "utc", desc = "Time zone of output date")
     },
     snippets = {
         @JinjavaSnippet(code = "{% content.updated|datetimeformat('%B %e, %Y') %}"),
@@ -29,12 +30,11 @@ public Object filter(Object var, JinjavaInterpreter interpreter,
       String... args) {
 
     if (args.length > 0) {
-      return Functions.dateTimeFormat(var, args[0]);
+      return Functions.dateTimeFormat(var, args);
     }
     else {
       return Functions.dateTimeFormat(var);
     }
-
   }
 
 }

src/main/java/com/hubspot/jinjava/lib/fn/Functions.java

@@ -2,7 +2,9 @@
 
 import static com.hubspot.jinjava.util.Logging.ENGINE_LOG;
 
+import java.time.DateTimeException;
 import java.time.Instant;
+import java.time.ZoneId;
 import java.time.ZoneOffset;
 import java.time.ZonedDateTime;
 import java.util.ArrayList;
@@ -21,6 +23,7 @@
 import com.hubspot.jinjava.doc.annotations.JinjavaSnippet;
 import com.hubspot.jinjava.interpret.InterpretException;
 import com.hubspot.jinjava.interpret.JinjavaInterpreter;
+import com.hubspot.jinjava.objects.date.InvalidDateFormatException;
 import com.hubspot.jinjava.objects.date.PyishDate;
 import com.hubspot.jinjava.objects.date.StrftimeFormatter;
 import com.hubspot.jinjava.tree.Node;
@@ -57,10 +60,27 @@ public static List<Object> immutableListOf(Object... items) {
 
   @JinjavaDoc(value = "formats a date to a string", params = {
       @JinjavaParam(value = "var", type = "date", defaultValue = "current time"),
-      @JinjavaParam(value = "format", defaultValue = StrftimeFormatter.DEFAULT_DATE_FORMAT)
+      @JinjavaParam(value = "format", defaultValue = StrftimeFormatter.DEFAULT_DATE_FORMAT),
+      @JinjavaParam(value = "timezone", defaultValue = "utc", desc = "Time zone of output date")
   })
   public static String dateTimeFormat(Object var, String... format) {
-    ZonedDateTime d = getDateTimeArg(var);
+
+    ZoneId zoneOffset = ZoneOffset.UTC;
+
+    if (format.length > 1) {
+      String timezone = format[1];
+      try {
+        zoneOffset = ZoneId.of(timezone);
+      } catch (DateTimeException e) {
+        throw new InvalidDateFormatException(timezone, e);
+      }
+    } else if (var instanceof ZonedDateTime) {
+      zoneOffset = ((ZonedDateTime) var).getZone();
+    } else if (var instanceof PyishDate) {
+      zoneOffset = ((PyishDate) var).toDateTime().getZone();
+    }
+
+    ZonedDateTime d = getDateTimeArg(var, zoneOffset);
 
     if (d == null) {
       return "";
@@ -78,18 +98,21 @@ public static String dateTimeFormat(Object var, String... format) {
     }
   }
 
-  private static ZonedDateTime getDateTimeArg(Object var) {
+  private static ZonedDateTime getDateTimeArg(Object var, ZoneId zoneOffset) {
 
     ZonedDateTime d = null;
 
     if (var == null) {
-      d = ZonedDateTime.now(ZoneOffset.UTC);
+      d = ZonedDateTime.now(zoneOffset);
     } else if (var instanceof Number) {
-      d = ZonedDateTime.ofInstant(Instant.ofEpochMilli(((Number) var).longValue()), ZoneOffset.UTC);
+      d = ZonedDateTime.ofInstant(Instant.ofEpochMilli(((Number) var).longValue()), zoneOffset);
     } else if (var instanceof PyishDate) {
-      d = ((PyishDate) var).toDateTime();
+      PyishDate pyishDate = ((PyishDate) var);
+      d = pyishDate.toDateTime();
+      d = d.withZoneSameInstant(zoneOffset);
     } else if (var instanceof ZonedDateTime) {
       d = (ZonedDateTime) var;
+      d = d.withZoneSameInstant(zoneOffset);
     } else if (!ZonedDateTime.class.isAssignableFrom(var.getClass())) {
       throw new InterpretException("Input to function must be a date object, was: " + var.getClass());
     }
@@ -101,7 +124,7 @@ private static ZonedDateTime getDateTimeArg(Object var) {
       @JinjavaParam(value = "var", type = "date", defaultValue = "current time"),
   })
   public static long unixtimestamp(Object var) {
-    ZonedDateTime d = getDateTimeArg(var);
+    ZonedDateTime d = getDateTimeArg(var, ZoneOffset.UTC);
 
     if (d == null) {
       return 0;

src/test/java/com/hubspot/jinjava/lib/filter/DateTimeFormatFilterTest.java

@@ -11,6 +11,7 @@
 
 import com.hubspot.jinjava.Jinjava;
 import com.hubspot.jinjava.interpret.JinjavaInterpreter;
+import com.hubspot.jinjava.objects.date.InvalidDateFormatException;
 import com.hubspot.jinjava.objects.date.StrftimeFormatter;
 
 public class DateTimeFormatFilterTest {
@@ -58,4 +59,20 @@ public void itHandlesVarsAndLiterals() throws Exception {
     assertThat(interpreter.getErrorsCopy()).isEmpty();
   }
 
+  @Test
+  public void itSupportsTimezones() throws Exception {
+    assertThat(filter.filter(1539277785000L, interpreter, "%B %d, %Y, at %I:%M %p")).isEqualTo("October 11, 2018, at 05:09 PM");
+    assertThat(filter.filter(1539277785000L, interpreter, "%B %d, %Y, at %I:%M %p", "America/New_York")).isEqualTo("October 11, 2018, at 01:09 PM");
+    assertThat(filter.filter(1539277785000L, interpreter, "%B %d, %Y, at %I:%M %p", "UTC+8")).isEqualTo("October 12, 2018, at 01:09 AM");
+  }
+
+  @Test(expected = InvalidDateFormatException.class)
+  public void itThrowsExceptionOnInvalidTimezone() throws Exception {
+    filter.filter(1539277785000L, interpreter, "%B %d, %Y, at %I:%M %p", "Not a timezone");
+  }
+
+  @Test(expected = InvalidDateFormatException.class)
+  public void itThrowsExceptionOnInvalidDateformat() throws Exception {
+    filter.filter(1539277785000L, interpreter, "Not a format");
+  }
 }