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Search API Reference for Amazon CloudSearch

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Submitting Suggest Requests in Amazon CloudSearch
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Search Service Errors

You use the Search API to submit search or suggestion requests to your Amazon CloudSearch domain. For more information about searching, see Searching Your Data with Amazon CloudSearch. For more information about suggestions, see Getting Autocomplete Suggestions in Amazon CloudSearch.

The other APIs you use to interact with Amazon CloudSearch are:

Configuration API—Set up and manage your search domain.
Document Service API—Submit the data you want to search.

Search

This section describes the HTTP request and response messages for the search resource.

Search Syntax


GET /2013-01-01/search

Search Request Headers

HOST

The search request endpoint for the domain you're querying. You can use DescribeDomains to retrieve your domain's search request endpoint.

Required: Yes

Search Request Parameters

cursor

Retrieves a cursor value you can use to page through large result sets. Use the size parameter to control the number of hits you want to include in each response. You can specify either the cursor or start parameter in a request, they are mutually exclusive. For more information, see Paginate the results.

To get the first cursor, specify cursor=initial in your initial request. In subsequent requests, specify the cursor value returned in the hits section of the response.

For example, the following request sets the cursor value to initial and the size parameter to 100 to get the first set of hits. The cursor for the next set of hits is included in the response.


search?q=john&cursor=initial&size=100&return=_no_fields
{
   "status": {
      "rid": "+/Xu5s0oHwojC6o=",
      "time-ms": 15
   },
   "hits": {
      "found": 503,
      "start": 0,
      "cursor": "VegKzpYYQW9JSVFFRU1UeWwwZERBd09EUTNPRGM9ZA",
      "hit": [
         {"id": "tt0120601"},
         {"id": "tt1801552"},
         ...
      ]
   }
}

To get the next set of hits, you specify the cursor value and the number of hits to retrieve.


search?q=john&cursor=VegKzpYYQW9JSVFFRU1UeWwwZERBd09EUTNPRGM9ZA&size=100

Type: String

Required: No

expr.NAME

Defines an expression that can be used to sort results. You can also specify an expression as a return field. For more information about defining and using expressions, see Configuring Expressions.

You can define and use multiple expressions in a search request. For example, the following request creates two expressions that are used to sort the results and includes them in the search results:


search?q=(and (term field=genres 'Sci-Fi')(term field=genres 'Comedy'))&q.parser=structured
&expr.expression1=_score*rating
&expr.expression2=(1/rank)*year
&sort=expression1 desc,expression2 desc
&return=title,rating,rank,year,_score,expression1,expression2

Type: String

Required: No

facet.FIELD

Specifies a field that you want to get facet information for—FIELD is the name of the field. The specified field must be facet enabled in the domain configuration. Facet options are specified as a JSON object. If the JSON object is empty, facet.FIELD={}, facet counts are computed for all field values, the facets are sorted by facet count, and the top 10 facets are returned in the results.

You can specify three options in the JSON object:

sort specifies how you want to sort the facets in the results: bucket or count. Specify bucket to sort alphabetically or numerically by facet value (in ascending order). Specify count to sort by the facet counts computed for each facet value (in descending order). To retrieve facet counts for particular values or ranges of values, use the buckets option instead of sort.
buckets specifies an array of the facet values or ranges you want to count. Buckets are returned in the order they are specified in the request. To specify a range of values, use a comma (,) to separate the upper and lower bounds and enclose the range using brackets or braces. A square bracket, [ or ], indicates that the bound is included in the range, a curly brace, { or }, excludes the bound. You can omit the upper or lower bound to specify an open-ended range. When omitting a bound, you must use a curly brace. The sort and size options are not valid if you specify buckets.
size specifies the maximum number of facets to include in the results. By default, Amazon CloudSearch returns counts for the top 10. The size parameter is only valid when you specify the sort option; it cannot be used in conjunction with buckets.

For example, the following request gets facet counts for the year field, sorts the facet counts by value and returns counts for the top three:


facet.year={sort:"bucket", size:3}

To specify which values or range of values you want to calculate facet counts for, use the buckets option. For example, the following request calculates and returns the facet counts by decade:


facet.year={buckets:["[1970,1979]","[1980,1989]",
             "[1990,1999]","[2000,2009]",
             "[2010,}"]}

You can also specify individual values as buckets:


facet.genres={buckets:["Action","Adventure","Sci-Fi"]}

Note that the facet values are case-sensitive—with the sample IMDb movie data, if you specify ["action","adventure","sci-fi"] instead of ["Action","Adventure","Sci-Fi"], all facet counts are zero.

Type: String

Required: No

format

Specifies the content type of the response.

Type: String

Valid Values: json|xml

Default: json

Required: No

fq

Specifies a structured query that filters the results of a search without affecting how the results are scored and sorted. You use fq in conjunction with the q parameter to filter the documents that match the constraints specified in the q parameter. Specifying a filter just controls which matching documents are included in the results, it has no effect on how they are scored and sorted. The fq parameter supports the full structured query syntax. For more information about using filters, see Filtering Matching Documents. For more information about structured queries, see Structured Search Syntax.

Type: String

Required: No

highlight.FIELD

Retrieves highlights for matches in the specified text or text-array field. Highlight options are specified as a JSON object. If the JSON object is empty, the returned field text is treated as HTML and the first match is highlighted with emphasis tags: search-term.

You can specify four options in the JSON object:

format—specifies the format of the data in the text field: text or html. When data is returned as HTML, all non-alphanumeric characters are encoded. The default is html.
max_phrases—specifies the maximum number of occurrences of the search term(s) you want to highlight. By default, the first occurrence is highlighted.
pre_tag—specifies the string to prepend to an occurrence of a search term. The default for HTML highlights is . The default for text highlights is *.
post_tag—specifies the string to append to an occurrence of a search term. The default for HTML highlights is . The default for text highlights is *.

Examples: highlight.plot={}, highlight.plot={format:'text',max_phrases:2,pre_tag:'',post_tag:''}

Type: String

Required: No

partial

Controls whether partial results are returned if one or more index partitions are unavailable. When your search index is partitioned across multiple search instances, by default Amazon CloudSearch only returns results if every partition can be queried. This means that the failure of a single search instance can result in 5xx (internal server) errors. When you specify partial=true. Amazon CloudSearch returns whatever results are available and includes the percentage of documents searched in the search results (percent-searched). This enables you to more gracefully degrade your users' search experience. For example, rather than displaying no results, you could display the partial results and a message indicating that the results might be incomplete due to a temporary system outage.

Type: Boolean

Default: False

Required: No

pretty

Formats JSON output so it's easier to read.

Type: Boolean

Default: False

Required: No

q

The search criteria for the request. How you specify the search criteria depends on the query parser used for the request and the parser options specified in the q.options parameter. By default, the simple query parser is used to process requests. To use the structured, lucene, or dismax query parser, you must also specify the q.parser parameter. For more information about specifying search criteria, see Searching Your Data with Amazon CloudSearch.

Type: String

Required: Yes

q.options

Configure options for the query parser specified in the q.parser parameter. The options are specified as a JSON object, for example: q.options={defaultOperator: 'or', fields: ['title^5','description']}.

The options you can configure vary according to which parser you use:

defaultOperator—The default operator used to combine individual terms in the search string. For example: defaultOperator: 'or'. For the dismax parser, you specify a percentage that represents the percentage of terms in the search string (rounded down) that must match, rather than a default operator. A value of 0% is the equivalent to OR, and a value of 100% is equivalent to AND. The percentage must be specified as a value in the range 0-100 followed by the percent (%) symbol. For example, defaultOperator: 50%. Valid values: and, or, a percentage in the range 0%-100% (dismax). Default: and (simple, structured, lucene) or 100 (dismax). Valid for: simple, structured, lucene, and dismax.
fields—An array of the fields to search when no fields are specified in a search. If no fields are specified in a search and this option is not specified, all statically configured text and text-array fields are searched. You can specify a weight for each field to control the relative importance of each field when Amazon CloudSearch calculates relevance scores. To specify a field weight, append a caret (^) symbol and the weight to the field name. For example, to boost the importance of the title field over the description field you could specify: fields: ['title^5','description']. Valid values: The name of any configured field and an optional numeric value greater than zero. Default: All statically configured text and text-array fields. Dynamic fields and literal fields are not searched by default. Valid for: simple, structured, lucene, and dismax.
operators—An array of the operators or special characters you want to disable for the simple query parser. If you disable the and, or, or not operators, the corresponding operators (+, |, -) have no special meaning and are dropped from the search string. Similarly, disabling prefix disables the wildcard operator (*) and disabling phrase disables the ability to search for phrases by enclosing phrases in double quotes. Disabling precedence disables the ability to control order of precedence using parentheses. Disabling near disables the ability to use the ~ operator to perform a sloppy phrase search. Disabling the fuzzy operator disables the ability to use the ~ operator to perform a fuzzy search. escape disables the ability to use a backslash (\) to escape special characters within the search string. Disabling whitespace is an advanced option that prevents the parser from tokenizing on whitespace, which can be useful for Vietnamese. (It prevents Vietnamese words from being split incorrectly.) For example, you could disable all operators other than the phrase operator to support just simple term and phrase queries: operators:['and', 'not', 'or', 'prefix']. Valid values: and, escape, fuzzy, near, not, or, phrase, precedence, prefix, whitespace. Default: All operators and special characters are enabled. Valid for: simple.
phraseFields—An array of the text or text-array fields you want to use for phrase searches. When the terms in the search string appear in close proximity within a field, the field scores higher. You can specify a weight for each field to boost that score. The phraseSlop option controls how much the matches can deviate from the search string and still be boosted. To specify a field weight, append a caret (^) symbol and the weight to the field name. For example, to boost phrase matches in the title field over the abstract field, you could specify: phraseFields:['title^3', 'abstract'] Valid values: The name of any text or text-array field and an optional numeric value greater than zero. Default: No fields. If you don't specify any fields with phraseFields, proximity scoring is disabled even if phraseSlop is specified. Valid for: dismax.
phraseSlop—An integer value that specifies how much matches can deviate from the search phrase and still be boosted according to the weights specified in the phraseFields option. For example, phraseSlop: 2. You must also specify phraseFields to enable proximity scoring. Valid values: positive integers. Default: 0. Valid for: dismax.
explicitPhraseSlop—An integer value that specifies how much a match can deviate from the search phrase when the phrase is enclosed in double quotes in the search string. (Phrases that exceed this proximity distance are not considered a match.) explicitPhraseSlop: 5. Valid values: positive integers. Default: 0. Valid for: dismax.
tieBreaker—When a term in the search string is found in a document's field, a score is calculated for that field based on how common the word is in that field compared to other documents. If the term occurs in multiple fields within a document, by default only the highest scoring field contributes to the document's overall score. You can specify a tieBreaker value to enable the matches in lower-scoring fields to contribute to the document's score. That way, if two documents have the same max field score for a particular term, the score for the document that has matches in more fields will be higher. The formula for calculating the score with a tieBreaker is:
```
(max field score) + (tieBreaker) * (sum of the scores for the rest of the matching fields)
```
For example, the following query searches for the term dog in the title, description, and review fields and sets tieBreaker to 0.1:
```
q=dog&q.parser=dismax&q.options={fields:['title', 'description', 'review'], tieBreaker: 0.1}
```
If dog occurs in all three fields of a document and the scores for each field are title=1, description=3, and review=1, the overall score for the term dog is:
```
3 +  0.1 * (1+1) = 3.2
```
Set tieBreaker to 0 to disregard all but the highest scoring field (pure max). Set to 1 to sum the scores from all fields (pure sum). Valid values: 0.0 to 1.0. Default: 0.0. Valid for: dismax.

Type: JSON object

Default: See individual option descriptions.

Required: No

q.parser

Specifies which query parser to use to process the request: simple, structured, lucene, and dismax. If q.parser is not specified, Amazon CloudSearch uses the simple query parser.

simple—perform simple searches of text and text-array fields. By default, the simple query parser searches all statically configured text and text-array fields. You can specify which fields to search by with the q.options parameter. If you prefix a search term with a plus sign (+) documents must contain the term to be considered a match. (This is the default, unless you configure the default operator with the q.options parameter.) You can use the - (NOT), | (OR), and * (wildcard) operators to exclude particular terms, find results that match any of the specified terms, or search for a prefix. To search for a phrase rather than individual terms, enclose the phrase in double quotes. For more information, see Searching Your Data with Amazon CloudSearch.