From 4d76d3bb5835412f62a81ab7390f9010c9cb17ec Mon Sep 17 00:00:00 2001
From: Gobi Selvaraj <gselvaraj@hubspot.com>
Date: Fri, 26 Feb 2021 11:24:20 -0500
Subject: [PATCH] Allow double underscore in the field name for filtering

---
 .../hubspot/httpql/impl/UriParamParser.java   | 31 +++++++++++++---
 .../httpql/impl/UriParamParserTest.java       | 36 +++++++++++++++++++
 2 files changed, 62 insertions(+), 5 deletions(-)

diff --git a/httpql/src/main/java/com/hubspot/httpql/impl/UriParamParser.java b/httpql/src/main/java/com/hubspot/httpql/impl/UriParamParser.java
index 1f44f30..5b362cb 100644
--- a/httpql/src/main/java/com/hubspot/httpql/impl/UriParamParser.java
+++ b/httpql/src/main/java/com/hubspot/httpql/impl/UriParamParser.java
@@ -14,6 +14,7 @@
 import org.apache.commons.lang.math.NumberUtils;
 import org.jooq.impl.DSL;
 
+import com.google.common.base.Joiner;
 import com.google.common.base.Splitter;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Multimap;
@@ -28,7 +29,9 @@ public class UriParamParser {
   public static final Map<String, Filter> BY_NAME = new HashMap<>();
   private static final ServiceLoader<Filter> LOADER = ServiceLoader.load(Filter.class);
 
-  private static final Splitter FILTER_PARAM_SPLITTER = Splitter.on("__").trimResults();
+  private static final String FILTER_PARAM_DELIMITER = "__";
+  private static final Splitter FILTER_PARAM_SPLITTER = Splitter.on(FILTER_PARAM_DELIMITER).trimResults();
+  private static final Joiner FILTER_PARAM_JOINER = Joiner.on(FILTER_PARAM_DELIMITER);
   private static final Splitter MULTIVALUE_PARAM_SPLITTER = Splitter.on(",").omitEmptyStrings().trimResults();
 
   static {
@@ -59,8 +62,12 @@ public ParsedUriParams parseUriParams(Multimap<String, String> uriParams) {
     return parseUriParams(multimapToMultivaluedMap(uriParams));
   }
 
-  @SuppressWarnings("rawtypes")
   public ParsedUriParams parseUriParams(Map<String, List<String>> uriParams) {
+    return parseUriParams(uriParams, false);
+  }
+
+  @SuppressWarnings("rawtypes")
+  public ParsedUriParams parseUriParams(Map<String, List<String>> uriParams, boolean allowDoubleUnderscoreInFieldName) {
 
     final ParsedUriParams result = new ParsedUriParams();
 
@@ -94,11 +101,11 @@ public ParsedUriParams parseUriParams(Map<String, List<String>> uriParams) {
 
     for (Map.Entry<String, List<String>> entry : params.entrySet()) {
       List<String> parts = FILTER_PARAM_SPLITTER.splitToList(entry.getKey().trim());
-      if (parts.size() > 2) {
+      if (parts.size() > 2 && !allowDoubleUnderscoreInFieldName) {
         continue;
       }
 
-      final String fieldName = parts.get(0);
+      final String fieldName = fieldNameFromParts(parts, allowDoubleUnderscoreInFieldName);
       final String filterName = filterNameFromParts(parts);
       final Filter filter = BY_NAME.get(filterName);
 
@@ -123,8 +130,22 @@ private static String filterNameFromParts(List<String> parts) {
     if (parts.size() == 1) {
       return (new Equal()).names()[0];
     } else {
-      return parts.get(1);
+      return parts.get(parts.size() - 1);
+    }
+  }
+
+  private static String fieldNameFromParts(List<String> parts, boolean allowDoubleUnderscoreInFieldName) {
+    if (!allowDoubleUnderscoreInFieldName) {
+      return parts.get(0);
     }
+
+    if (BY_NAME.keySet().contains(parts.get(parts.size() - 1))) {
+      List<String> partsCopy = new ArrayList<>(parts);
+      partsCopy.remove(parts.size() - 1);
+      return FILTER_PARAM_JOINER.join(partsCopy);
+    }
+
+    return FILTER_PARAM_JOINER.join(parts);
   }
 
   public static Builder newBuilder() {
diff --git a/httpql/src/test/java/com/hubspot/httpql/impl/UriParamParserTest.java b/httpql/src/test/java/com/hubspot/httpql/impl/UriParamParserTest.java
index 92f7d8d..6d7d347 100644
--- a/httpql/src/test/java/com/hubspot/httpql/impl/UriParamParserTest.java
+++ b/httpql/src/test/java/com/hubspot/httpql/impl/UriParamParserTest.java
@@ -1,6 +1,7 @@
 package com.hubspot.httpql.impl;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
 
 import java.util.Collections;
 import java.util.HashMap;
@@ -11,6 +12,8 @@
 import org.junit.Before;
 import org.junit.Test;
 
+import com.hubspot.httpql.error.FilterViolation;
+
 public class UriParamParserTest {
   UriParamParser uriParamParser;
 
@@ -42,4 +45,37 @@ public void itPreservesCommasInEqValues() {
     assertThat(parsedUriParams.getFieldFilters().get(0).getValue()).isEqualTo("1,2,3");
   }
 
+  @Test
+  public void itAllowsDoubleUnderscoresInFieldNames() {
+    Map<String, List<String>> query = new HashMap<>();
+    query.put("foo1__bar1__eq", Lists.newArrayList("1"));
+    query.put("foo2__bar2__contains", Lists.newArrayList("1"));
+    query.put("foo3__eq", Lists.newArrayList("1"));
+    query.put("foo4", Lists.newArrayList("1"));
+
+    final ParsedUriParams parsedUriParams = uriParamParser.parseUriParams(query, true);
+
+    assertThat(parsedUriParams.getFieldFilters().get(0).getField()).isEqualTo("foo2__bar2");
+    assertThat(parsedUriParams.getFieldFilters().get(0).getFilterName()).isEqualTo("contains");
+
+    assertThat(parsedUriParams.getFieldFilters().get(1).getField()).isEqualTo("foo3");
+    assertThat(parsedUriParams.getFieldFilters().get(1).getFilterName()).isEqualTo("eq");
+
+    assertThat(parsedUriParams.getFieldFilters().get(2).getField()).isEqualTo("foo1__bar1");
+    assertThat(parsedUriParams.getFieldFilters().get(2).getFilterName()).isEqualTo("eq");
+
+    assertThat(parsedUriParams.getFieldFilters().get(3).getField()).isEqualTo("foo4");
+    assertThat(parsedUriParams.getFieldFilters().get(3).getFilterName()).isEqualTo("eq");
+  }
+
+  @Test
+  public void itRequiresExplicitEqualFilterWithDoubleUnderscoreInFieldNames() {
+    Map<String, List<String>> query = new HashMap<>();
+    query.put("foo2__bar2", Lists.newArrayList("1"));
+
+    assertThatThrownBy(
+        () -> uriParamParser.parseUriParams(query, true)
+    )
+        .isInstanceOf(FilterViolation.class);
+  }
 }