Sometimes, specific terms can act as cues that you can use to filter down the hits that your users get.
For example, imagine you have a website where people can search for dishes from restaurants with home-delivery service. If someone types “gluten-free”, you could use this to filter out any dish that has “gluten” in its list of allergens.
To do this, you can leverage Algolia’s Rules and trigger custom filters based on what users search for.
Positive Filters
Imagine you want to allow users who search for dishes to automatically filter out every non-diet-friendly dish whenever their search query contains the term “diet”. A good approach would be to leverage the special attribute _tags and use it to categorize dishes depending on their individual qualities:
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| [
{
"name": "Chicken Stuffed Baked Avocados",
"restaurant": "The Hive",
"_tags": ["low-carb"]
},
{
"name": "Spinach Quiche",
"restaurant": "Bert's Inn",
"_tags": ["low-carb", "vegetarian"]
},
{
"name": "Pizza Chicken Bake",
"restaurant": "Millbrook Deli",
"_tags": ["cheese"]
},
{
"name": "Strawberry Sorbet",
"restaurant": "The Hive",
"_tags": ["low-fat", "vegetarian", "vegan"]
}
]
|
When users add “diet” in their search, you want to automatically bring in every record that has “low-carb” or “low-fat” in their _tags attribute. Because _tags comes ready and optimized for filtering, you don’t have to set it as an attribute for faceting. You can directly create a new Rule that detects the term “diet” in a query, and applies a positive filter on tags “low-carb” and “low-fat”.
Note that you also need to add a consequence in your Rule to remove the word “diet” from your query. This way, it won’t be used as a search term, only for filtering purposes.
Using the API
To add a Rule, you need to use the saveRule method. When setting a Rule, you need to define a condition and a consequence.
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| $rule = [
'objectID' => 'diet-rule',
'conditions' => array(array(
'pattern' => 'diet',
'anchoring' => 'contains',
)),
'consequence' => [
'params' => [
'filters' => '"low-carb" OR "low-fat"',
'query' => [
'edits' => [
[
'type' => 'remove',
'delete' => 'diet'
]
]
]
]
]
];
$response = $index->saveRule($rule);
|
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| rule = {
objectID: 'diet-rule',
conditions: [{
pattern: 'diet',
anchoring: 'contains'
}],
consequence: {
params: {
filters: '"low-carb" OR "low-fat"',
query: {
edits: [
{
type: 'remove',
delete: 'diet'
}
]
}
}
}
}
index.save_rule(rule)
|
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| const rule = {
objectID: 'diet-rule',
conditions: [{
pattern: 'diet',
anchoring: 'contains'
}],
consequence: {
params: {
filters: '"low-carb" OR "low-fat"',
query: {
edits: [
{
type: 'remove',
delete: 'diet'
}
]
}
}
}
};
index.saveRule(rule).then(() => {
// done
});
|
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| rule = {
'objectID': 'diet-rule',
'conditions': [{
'pattern': 'diet',
'anchoring': 'contains'
}],
'consequence': {
'params': {
'filters': '"low-carb" OR "low-fat"',
'query': {
'edits': [{
'type': 'remove',
'delete': 'diet'
}]
}
}
}
}
response = index.save_rule(rule)
|
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| let rule = Rule(objectID: "diet-rule")
.set(\.conditions, to: [
Rule.Condition()
.set(\.anchoring, to: .contains)
.set(\.pattern, to: .literal("diet"))
])
.set(\.consequence, to: Rule.Consequence()
.set(\.queryTextAlteration, to: .edits([.remove("diet")]))
.set(\.query, to: Query().set(\.filters, to: "\"low-carb\" OR \"low-fat\""))
)
index.saveRule(rule) { result in
if case .success(let response) = result {
print("Response: \(response)")
}
}
|
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| var rule = new Rule
{
ObjectID = "diet-rule",
Conditions = new List<Condition>
{
new Condition { Anchoring = "contains", Pattern = "diet" }
},
Consequence = new Consequence
{
Params = new ConsequenceParams
{
Filters = "'low-carb' OR 'low-fat'"
Edits = new List<Edit>
{
new Edit {Type = EditType.Remove, Delete = "diet"}
}
}
}
};
index.SaveRule(rule);
// Asynchronous
await index.SaveRuleAsync(rule);
|
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| Condition condition = new Condition()
.setPattern("diet")
.setAnchoring("contains");
ConsequenceQuery consequenceQuery =
new ConsequenceQuery().setEdits(Collections.singletonList(new Edit().setType("remove").setDelete("diet")));
ConsequenceParams params = new ConsequenceParams();
params.setConsequenceQuery(consequenceQuery);
params.setFilters("'low-carb' OR 'low-fat'");
Consequence consequence = new Consequence().setParams(params);
Rule rule = new Rule()
.setObjectID("diet-rule")
.setCondition(Collections.singletonList(condition))
.setConsequence(consequence);
index.saveRule(rule);
|
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| rule := search.Rule{
ObjectID: "diet-rule",
Condition: []search.RuleCondition{{Anchoring: search.Contains, Pattern: "diet"}},
Consequence: search.RuleConsequence{
Params: &search.RuleParams{
Query: search.NewRuleQueryObject(
search.RuleQueryObjectQuery{
Edits: []search.QueryEdit{
search.RemoveEdit("diet"),
},
},
),
QueryParams: search.QueryParams{
Filters: opt.Filters("'low-carb' OR 'low-fat'"),
},
},
},
}
res, err := index.SaveRule(rule)
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| val ruleToSave = Rule(
objectID = "diet-rule",
conditions = Some(Seq(Condition(
pattern = "diet",
anchoring = "contains"
))),
consequence = Consequence(
params = Seq(
Map("filters" -> "'low-carb' OR 'low-fat'"),
Map(
"query" -> Map(
"edits" -> Seq(
Edit("remove", "diet")
)
)
)
)
),
)
client.execute {
save rule ruleToSave inIndex "index_name"
}
|
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| val rules = rules {
rule(
"diet-rule",
listOf(Condition(Contains, Literal("diet"))),
Consequence(
edits = edits { +"diet" },
query = query {
filters {
orTag {
tag("low-carb")
tag("low-fat")
}
}
}
)
)
}
index.saveRules(rules)
|
Using the dashboard
You can also add your Rules in your Algolia dashboard.
- Select the Search product icon on your dashboard.
- Select the Rules section from the left sidebar menu in the Algolia dashboard.
- Under the heading Rules, select the index you are adding a Rule to.
- Select Create your first rule or New rule. In the dropdown, click on the Manual Editor option.
- In the Condition(s) sections, keep Query contains and enter “diet” in the input field.
- In the Consequence(s) section:
- Click the Add consequence button and select Add Query Parameter.
- In the input field that appears, enter the JSON search parameter you want to add. For example:
{ "filters": "'low-carb' OR 'low-fat'" }.
- Click the Add consequence button again and select Remove Word.
- Type or select “diet” in the input field.
- Don’t forget to save your changes.
Negative Filters
Imagine you want to allow users who search for dishes to automatically filter out every non-gluten-free dish whenever their search query contains the term “gluten-free”.
You could add “Gluten-free” in the title (e.g., “Gluten-free Pasta Dough”) but this would force you to do it for every dish that doesn’t contain gluten, even those that don’t typically do (e.g., “Leek Soup” or “Fruit Salad”). When a user is looking for “gluten-free” dishes, it’s safer to assume they want everything that matches their search and doesn’t have gluten, not that they’re looking for dishes with the words “Gluten-free” in the title.
You could maintain a list of tags (with the special _tags attribute), but you may want to keep allergens separate, especially if you don’t want to make them searchable.
Instead, a better approach is to create a more explicit list with all allergens:
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| [
{
"name": "Pasta Bolognese",
"restaurant": "Millbrook Deli",
"allergens": ["eggs", "lactose"]
},
{
"name": "Breakfast Waffles",
"restaurant": "The Hive",
"allergens": ["gluten", "lactose"]
}
]
|
When users add “gluten-free” in their search, you want to automatically filter out every record that has “gluten” in their allergens attribute. To do so, you first need to set allergens in your list of attributes for faceting. Then, you can create a new Rule that filters out unwanted records based on the allergens facet values.
Using the API
First, you need to set allergens as attributesForFaceting. This happens at indexing time.
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| $index->setSettings([
'attributesForFaceting' => [
"allergens"
]
]);
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| index.set_settings({
attributesForFaceting: [
'allergens'
]
})
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| index.setSettings({
attributesForFaceting: [
'allergens'
]
}).then(() => {
// done
});
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| index.set_settings({
'attributesForFaceting': [
'allergens'
]
})
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| let settings = Settings()
.set(\.attributesForFaceting, to: ["allergens"])
index.setSettings(settings) { result in
if case .success(let response) = result {
print("Response: \(response)")
}
}
|
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| IndexSettings settings = new IndexSettings
{
AttributesForFaceting = new List<string>
{
"allergens"
}
};
index.SetSettings(settings);
// Asynchronous
await index.SetSettingsAsync(settings);
|
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| index.setSettings(new IndexSettings().setAttributesForFaceting(Collections.singletonList("allergens")));
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| res, err := index.SetSettings(search.Settings{
AttributesForFaceting: opt.AttributesForFaceting("allergens"),
})
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| client.execute {
changeSettings of "myIndex" `with` IndexSettings(
attributesForFaceting = Some(Seq(
"allergens"
))
)
}
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| val settings = settings {
attributesForFaceting {
+"allergens"
}
}
index.setSettings(settings)
|
Then, you can set a Rule that detects the term “gluten-free” in a query, and applies a negative filter on facet value allergens:gluten. For this, you need to use the saveRule method.
Note that you also need to add a consequence in your Rule to remove the word “gluten-free” from your query. This way, it won’t be used as a search term, only for filtering purposes.
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| $rule = [
'objectID' => 'gluten-free-rule',
'conditions' => array(array(
'pattern' => 'gluten-free',
'anchoring' => 'contains',
))
'consequence' => [
'params' => [
'filters' => 'NOT allergens:gluten',
'query' => [
'edits' => [
'type' => 'remove',
'delete' => 'gluten-free'
]
]
]
]
];
$response = $index->saveRule($rule['objectID'], $rule);
|
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| rule = {
objectID: 'gluten-free-rule',
conditions: [{
pattern: 'gluten-free',
anchoring: 'contains'
}],
consequence: {
params: {
filters: 'NOT allergens:gluten',
query: {
edits: [
type: 'remove',
delete: 'gluten-free'
]
}
}
}
}
index.save_rule(rule)
|
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| const rule = {
objectID: 'gluten-free-rule',
conditions: [{
pattern: 'gluten-free',
anchoring: 'contains'
}],
consequence: {
params: {
filters: 'NOT allergens:gluten',
query: {
edits: [
type: 'remove',
delete: 'gluten-free'
]
}
}
}
};
index.saveRule(rule).then(() => {
// done
});
|
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| rule = {
'objectID': 'gluten-free-rule',
'conditions': [{
'pattern': 'gluten-free',
'anchoring': 'contains'
}],
'consequence': {
'params': {
'filters': 'NOT allergens:gluten',
'query': {
'edits': [{
'type': 'remove',
'delete': 'gluten-free'
}]
}
}
}
}
response = index.save_rule(rule)
|
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| let rule = Rule(objectID: "gluten-free-rule")
.set(\.conditions, to: [
Rule.Condition()
.set(\.anchoring, to: .contains)
.set(\.pattern, to: .literal("gluten-free"))
])
.set(\.consequence, to: Rule.Consequence()
.set(\.queryTextAlteration, to: .edits([.remove("gluten-free")]))
.set(\.query, to: Query().set(\.filters, to: "NOT allergens:gluten"))
)
index.saveRule(rule) { result in
if case .success(let response) = result {
print("Response: \(response)")
}
}
|
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| var rule = new Rule
{
ObjectID = "gluten-free-rule",
Conditions = new List<Condition>
{
new Condition { Anchoring = "contains", Pattern = "gluten-free" }
},
Consequence = new Consequence
{
Params = new ConsequenceParams
{
Filters = "NOT allergens:gluten"
Edits = new List<Edit>
{
new Edit {Type = EditType.Remove, Delete = "gluten-free"}
}
}
}
};
index.SaveRule(rule);
// Asynchronous
await index.SaveRuleAsync(rule);
|
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| Condition condition = new Condition().setPattern("gluten-free").setAnchoring("contains");
ConsequenceQuery consequenceQuery =
new ConsequenceQuery().setEdits(Collections.singletonList(new Edit().setType("remove").setDelete("gluten-free")));
ConsequenceParams params = new ConsequenceParams();
params.setConsequenceQuery(consequenceQuery);
params.setFilters("NOT allergens:gluten");
Consequence consequence = new Consequence().setParams(params);
Rule rule =
new Rule()
.setObjectID("gluten-free-rule")
.setCondition(Collections.singletonList(condition))
.setConsequence(consequence);
index.saveRule(rule);
|
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| rule := search.Rule{
ObjectID: "gluten-free-rule",
Conditions: []search.RuleCondition{{Anchoring: search.Contains, Pattern: "gluten-free"}},
Consequence: search.RuleConsequence{
Params: &search.RuleParams{
Query: search.NewRuleQueryObject(
search.RuleQueryObjectQuery{
Edits: []search.QueryEdit{
search.RemoveEdit("gluten-free"),
},
},
),
QueryParams: search.QueryParams{
Filters: opt.Filters("NOT allergens:gluten"),
},
},
},
}
res, err := index.SaveRule(rule)
|
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| val ruleToSave = Rule(
objectID = "gluten-free-rule",
conditions = Some(Seq(Condition(
pattern = "gluten-free",
anchoring = "contains"
))),
consequence = Consequence(
params = Seq(
Map("filters" -> "NOT allergens:gluten"),
Map(
"query" -> Map(
"edits" -> Seq(
Edit("remove", "gluten-free")
)
)
)
)
),
)
client.execute {
save rule ruleToSave inIndex "index_name"
}
|
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| val rules = rules {
rule(
"gluten-free-rule",
listOf(Condition(Contains, Literal("gluten-free"))),
Consequence(
edits = edits { +"gluten-free" },
query = query {
filters { and { facet("allergens", "gluten", isNegated = true) } }
}
)
)
}
index.saveRules(rules)
|
Using the dashboard
You can also add your Rules in your Algolia dashboard.
- Select the Search product icon on your dashboard and then select your index.
- Click the Configuration tab.
- In the Facets subsection of Filtering and Faceting, click the “Add an attribute” button and select the
allergens attribute from the dropdown.
- Click the Rules tab.
- Select Create your first rule or New rule. In the dropdown, click on the Manual Editor option.
- In the Condition(s) section, keep Query toggled on, select Contains in the dropdown, and enter “gluten-free” in the input field.
- In the Consequence(s) section:
- Click the Add consequence button and select Add Query Parameter.
- In the input field that appears, enter the JSON search parameter you want to add. For example:
{ "filters": "NOT allergens:gluten" }
- Click the Add consequence button again and select Remove Word.
- Type or select “gluten-free” in the input field.
- Don’t forget to save your changes.
Numerical filtering
Use Case
Imagine the query “cheap toaster 800w”. Rules can be used to filter the results by “toaster” and “prices between 0 and 25”, so that the only textual search is the remaining term, “800w”, which could further be used to limit the results with that wattage.
Rule
If query = “cheap toaster” then price < 10 and type=toaster
Note: This requires 2 Rules.
Using the API
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| // Turn JSON into an array
$rules = array(
array(
'objectID' => 'cheap',
'condition' => array(
'pattern' => 'cheap',
'anchoring' => 'contains'
),
'consequence' => array(
'params' => array(
'query' => array(
'remove' => 'cheap'
),
'filters' => 'price < 10'
)
)
)
);
// Push Rule to index
$index->batchRules($rules);
|
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| rule = {
objectID: 'cheap',
condition: {
pattern: 'cheap',
anchoring: 'contains'
},
consequence: {
params: {
query: {
remove: 'cheap'
}
},
filters: 'price < 10'
}
}
index.save_rule(rule['objectID'], rule)
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| index.saveRule({
objectID: 'cheap',
condition: {
pattern: 'cheap',
anchoring: 'contains',
},
consequence: {
params: {
query: {
remove: 'cheap',
},
},
filters: 'price < 10',
},
});
|
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| rule = {
'objectID': 'cheap',
'condition': {
'pattern': 'cheap',
'anchoring': 'contains'
},
'consequence': {
'params': {
'query': {
'remove': 'cheap'
}
}
},
'filters': 'price < 10'
}
response = index.save_rule(rule)
|
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| let rule = Rule(objectID: "cheap")
.set(\.conditions, to: [
Rule.Condition()
.set(\.anchoring, to: .contains)
.set(\.pattern, to: .literal("cheap"))
])
.set(\.consequence, to: Rule.Consequence()
.set(\.queryTextAlteration, to: .edits([.remove("cheap")]))
.set(\.query, to: Query().set(\.filters, to: "price < 10"))
)
index.saveRule(rule) { result in
if case .success(let response) = result {
print("Response: \(response)")
}
}
|
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| var rule = new Rule
{
ObjectID = "cheap",
Conditions = new List<Condition> {
new Condition { Anchoring = "contains", Pattern = "cheap" }
},
Consequence = new Consequence
{
Params = new ConsequenceParams {
Filters = "price < 10",
Query = new ConsequenceQuery {
Edits = new List<Edit> {
new Edit {
Type = EditType.Remove,
Delete = "cheap"
}
}
}
}
}
};
index.SaveRule(rule);
// Asynchronous
await index.SaveRuleAsync(rule);
|
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| Condition condition = new Condition()
.setPattern("cheap")
.setAnchoring("contains");
ConsequenceQuery consequenceQuery = new ConsequenceQuery()
.setEdits(Collections.singletonList(new Edit().setType("remove").setDelete("cheap")));
ConsequenceParams params = new ConsequenceParams()
.setConsequenceQuery(consequenceQuery).setFilters("price < 10");
Consequence consequence = new Consequence()
.setParams(params);
Rule rule = new Rule()
.setObjectID("cheap")
.setConditions(Collections.singletonList(condition))
.setConsequence(consequence);
// Synchronous
index.saveRule(rule);
// Asynchronous
index.saveRuleAsync(rule);
|
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| rule := search.Rule{
ObjectID: "cheap",
Condition: search.RuleCondition{Anchoring: search.Contains, Pattern: "cheap"},
Consequence: search.RuleConsequence{
Params: &search.RuleParams{
Query: search.NewRuleQueryObject(
search.RuleQueryObjectQuery{
Edits: []search.QueryEdit{
search.RemoveEdit("cheap"),
},
},
),
QueryParams: search.QueryParams{
OptionalFilters: opt.Filter("price < 10"),
},
},
},
}
res, err := index.SaveRule(rule)
|
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| val ruleToSave = Rule(
objectID = "cheap",
condition = Condition(
pattern = "cheap",
anchoring = "contains"
),
consequence = Consequence(
params = Seq(
Map("Filters" -> "price < 10"),
Map(
"query" -> Map(
"edits" -> Seq(
Edit("remove", "cheap")
)
)
)
)
),
)
client.execute {
save rule ruleToSave inIndex "index_name"
}
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| val rules = rules {
rule(
"cheap",
conditions {
+condition(Contains, Literal("cheap"))
},
consequence(
edits = edits { +"cheap" },
query = query {
filters {
and { comparison("price", Less, 10) }
}
}
)
)
}
index.saveRules(rules)
|
Using the dashboard
Since there are two Rules, you’ll need to set up both separately.
Preparation
- Select the Search product icon on your dashboard and then select your index.
- Click the Configuration tab.
- In the Facets subsection of Filtering and Faceting, click the “Add an attribute” button and select the
product_type attribute from the dropdown.
For the first Rule
- Select the Rules section from the left sidebar menu in the Algolia dashboard.
- Under the heading Rules, select the index you are adding a Rule to.
- Select Create your first rule or New rule. In the dropdown, click on the Manual Editor option.
- In the Condition(s) section, keep Query toggled on, select Contains in the dropdown, and enter “toaster” in the input field.
- In the Consequence(s) section:
- Click the Add consequence button and select Add Query Parameter.
- In the input field that appears, add the JSON parameters you want to apply when the user’s query matches the Rule:
{ "filters": "product_type:toaster" }
- Click the Add consequence button again and select Remove Word.
- Type or select “toaster” in the input field.
- Don’t forget to save your changes.
For the second Rule
- Go back to the Rules section.
- Select New rule. In the dropdown, click on the Manual Editor option.
- In the Condition(s) section, keep Query toggled on, select Contains in the dropdown, and enter “cheap” in the input field.
- In the Consequence(s) section:
- Click the Add consequence button and select Add Query Parameter.
- In the input field that appears, add the JSON parameters you want to apply when the user’s query matches the Rule:
{ "filters": "price<10" }
- Click the Add consequence button again and select Remove Word.
- Type or select “cheap” in the input field.
- Don’t forget to save your changes.
