Components of a Request#

The ADC API has two classes of endpoints. The endpoints that respond to GET requests are simple services that require few or no parameters. While, the endpoints that response to POST requests are the main query services and provide many parameters for specifying the query as well as the data in the API response.

A typical POST query request specifies the following parameters:

  • The filters parameter specifies the query.

  • The from and size parameters specify the number of results to skip and the maximum number of results to be returned in the response.

  • The fields parameter specifies which data elements to be returned in the response. By default all fields (AIRR and non-AIRR) stored in the data repository are returned. This can vary between data repositories based upon how the repository decides to store blank or null fields, so the fields and/or include_fields parameter should be used to guarantee the existence of data elements in the response.

  • The include_fields parameter specifies the set of AIRR fields to be included in the response. This parameter can be used in conjunction with the fields parameter, in which case the list of fields is merged. This is a mechanism to ensure that specific, well-defined sets of AIRR data elements are returned without requiring all of those fields to be individually provided in the fields parameter.

The sets that can be requested are summarized in the table below.

include_fields

MiAIRR

AIRR required

AIRR identifiers

other AIRR fields

miairr

Y

some

N

N

airr-core

Y

Y

Y

N

airr-schema

Y

Y

Y

Y

Service Status Example

The following is an example GET request to check that the service API is available for VDJServer’s data repository.

curl https://vdjserver.org/airr/v1

The response should indicate success.

{"result":"success"}

Service Info Example

The following is an example GET request to get information about the service.

curl https://vdjserver.org/airr/v1/info

The response provides various information.

{
  "title": "api-js-tapis",
  "description": "AIRR Data Commons API for VDJServer Community Data Portal",
  "version": "2.0.0",
  "contact": {
    "name": "VDJServer",
    "url": "http://vdjserver.org/",
    "email": "vdjserver@utsouthwestern.edu"
  },
  "license": {
    "name": "GNU AGPL V3"
  },
  "api": {
    "title": "AIRR Data Commons API",
    "version": "1.0.0",
    "contact": {
      "name": "AIRR Community",
      "url": "http://www.airr-community.org/",
      "email": "join@airr-community.org"
    },
    "description": "Major Version 1 of the Adaptive Immune Receptor Repertoire (AIRR) data repository web service application programming interface (API).\n",
    "license": {
      "name": "Creative Commons Attribution 4.0 International",
      "url": "https://creativecommons.org/licenses/by/4.0/"
    }
  },
  "schema": {
    "title": "AIRR Schema",
    "description": "Schema definitions for AIRR standards objects",
    "version": "1.3",
    "contact": {
      "name": "AIRR Community",
      "url": "https://github.com/airr-community"
    },
    "license": {
      "name": "Creative Commons Attribution 4.0 International",
      "url": "https://creativecommons.org/licenses/by/4.0/"
    }
  },
  "max_size": 1000,
  "max_query_size": 2097152
}

Query Repertoire Example

The following is an example POST request to the repertoire endpoint of the ADC API. It queries for repertoires of human TCR beta receptors (filters), skips the first 10 results (from), requests 5 results (size), and requests only the repertoire_id field (fields).

curl --data @query1-2_repertoire.json -H 'content-type: application/json' https://vdjserver.org/airr/v1/repertoire

The content of the JSON payload.

{
    "filters":{
        "op":"and",
        "content": [
            {
                "op":"=",
                "content": {
                    "field":"subject.species.id",
                    "value":"NCBITAXON:9606"
                }
            },
            {
                "op":"=",
                "content": {
                    "field":"sample.pcr_target.pcr_target_locus",
                    "value":"TRB"
                }
            }
        ]
    },
    "from":10,
    "size":5,
    "fields":["repertoire_id"]
}

The response contains two JSON objects, an Info object that provides information about the API response and a Repertoire object that contains the list of Repertoires that met the query search criteria. In this case, the query returns a list of five repertoire identifiers. Note the Info object is based on the info block as specified in the OpenAPI v2.0 specification.

{
  "Info":
  {
      "title": "AIRR Data Commons API reference implementation",
      "description": "API response for repertoire query",
      "version": 1.3,
      "contact":
      {
          "name": "AIRR Community",
          "url": "https://github.com/airr-community"
      }
  },
  "Repertoire":
  [
      {"repertoire_id": "5993695857891348971-242ac118-0001-012"},
      {"repertoire_id": "5981154557681996267-242ac118-0001-012"},
      {"repertoire_id": "6018649617881108971-242ac118-0001-012"},
      {"repertoire_id": "5959121371158548971-242ac118-0001-012"},
      {"repertoire_id": "5939278622251028971-242ac118-0001-012"}
  ]
}

Request Parameters#

The ADC API supports the follow query parameters. These are only applicable to the query endpoints, i.e. the HTTP POST endpoints.

Parameter

Default

Description

filters

null

Specifies logical expression for query critieria

format

JSON

Specifies the API response format: JSON, AIRR TSV

include_fields

null

Specifies the set of AIRR fields to be included in the response

fields

null

Specifies which fields to include in the response

from

0

Specifies the first record to return from a set of search results

size

repository dependent

Specifies the number of results to return

facets

null

Provide aggregate count information for the specified fields

Filters Query Parameter

The filters parameter enables passing complex query criteria to the ADC API. The parameter represents the query in a JSON object.

A filters query consists of an operator (or a nested set of operators) with a set of field and value operands. The query criteria as represented in a JSON object can be considered an expression tree data structure where internal nodes are operators and child nodes are operands. The expression tree can be of any depth, and recursive algorithms are typically used for tree traversal.

The following operators are support by the ADC API.

Operator

Operands

Value Data Types

Description

Example

=

field and value

string, number, integer, or boolean

equals

{“op”:”=”,”content”:{“field”:”junction_aa”,”value”:”CASSYIKLN”}}

!=

field and value

string, number, integer, or boolean

does not equal

{“op”:”!=”,”content”:{“field”:”subject.organism.id”,”value”:”9606”}}

<

field and value

number, integer

less than

{“op”:”<”,”content”:{“field”:”sample.cell_number”,”value”:1000}}

<=

field and value

number, integer

less than or equal

{“op”:”<=”,”content”:{“field”:”sample.cell_number”,”value”:1000}}

>

field and value

number, integer

greater than

{“op”:”>”,”content”:{“field”:”sample.cells_per_reaction”,”value”:10000}}

>=

field and value

number, integer

greater than or equal

{“op”:”>=”,”content”:{“field”:”sample.cells_per_reaction”,”value”:10000}}

is missing

field

n/a

field is missing or is null

{“op”:”is missing”,”content”:{“field”:”sample.tissue”}}

is

field

n/a

identical to “is missing” operator, provided for GDC compatibility

{“op”:”is”,”content”:{“field”:”sample.tissue”}}

is not missing

field

n/a

field is not missing and is not null

{“op”:”is not missing”,”content”:{“field”:”sample.tissue”}}

not

field

n/a

identical to “is not missing” operator, provided for GDC compatibility

{“op”:”not”,”content”:{“field”:”sample.tissue”}}

in

field, multiple values in a list

array of string, number, or integer

matches a string or number in a list

{“op”:”in”,”content”:{“field”:”subject.strain_name”,”value”:[“C57BL/6”,”BALB/c”,”NOD”]}}

exclude

field, multiple values in a list

array of string, number, or integer

does not match any string or number in a list

{“op”:”exclude”,”content”:{“field”:”subject.strain_name”,”value”:[“SCID”,”NOD”]}}

contains

field, value

string

contains the substring

{“op”:”contains”,”content”:{“field”:”study.study_title”,”value”:”cancer”}}

and

multiple operators

n/a

logical AND

{“op”:”and”,”content”:[
{“op”:”!=”,”content”:{“field”:”subject.organism.id”,”value”:”9606”}},
{“op”:”>=”,”content”:{“field”:”sample.cells_per_reaction”,”value”:10000}},
{“op”:”exclude”,”content”:{“field”:”subject.strain_name”,”value”:[“SCID”,”NOD”]}}
]}

or

multiple operators

n/a

logical OR

{“op”:”or”,”content”:[
{“op”:”<”,”content”:{“field”:”sample.cell_number”,”value”:1000}},
{“op”:”is missing”,”content”:{“field”:”sample.tissue”}},
{“op”:”exclude”,”content”:{“field”:”subject.organism.id”,”value”:[“9606”,”10090”]}}
]}

Note that the not operator is different from a logical NOT operator, and the logical NOT is not needed as the other operators provide negation.

The field operand specifies a fully qualified property name in the AIRR Data Model. Fully qualified AIRR properties are either a JSON/YAML base type (string, number, integer, or boolean) or an array of one of these base types (some AIRR fields are arrays e.g. study.keywords_study). The Fields section below describes the available queryable fields.

The value operand specifies one or more values when evaluating the operator for the field operand.

Queries Against Arrays

A number of fields in the AIRR Data Model are arrays, such as study.keywords_study which is an array of strings or subject.diagnosis which is an array of Diagnosis objects. A query operator on an array field will apply that operator to each entry in the array to decide if the query filter is satisfied. The behavior is different for various operators. For operators such as = and in, the filter behaves like the Boolean OR over the array entries, that is if any array entry evaluates to true then the query filter is satisfied. For operators such as != and exclude, the filter behaves like the Boolean AND over the array entries, that is all array entries must evaluate to true for the query filter to be satisfied.

Examples

A simple query with a single operator looks like this:

{
  "filters": {
    "op":"=",
    "content": {
      "field":"junction_aa",
      "value":"CASSYIKLN"
    }
  }
}

A more complex query with multiple operators looks like this:

{
  "filters": {
    "op":"and",
    "content": [
      {
        "op":"!=",
        "content": {
          "field":"subject.organism.id",
          "value":"9606"
        }
      },
      {
        "op":">=",
        "content": {
          "field":"sample.cells_per_reaction",
          "value":"10000"
        }
      },
      {
        "op":"exclude",
        "content": {
          "field":"subject.organism.id",
          "value": ["9606", "10090"]
        }
      }
    ]
  }
}

Format Query Parameter

Specifies the format of the API response. json is the default format and is available for all endpoints. The rearrangement POST endpoint also accepts tsv which will provide the data in the AIRR TSV format. A specific ordering of fields in the TSV format should not be assumed from one API request to another. Take care to properly merge AIRR TSV data from multiple API requests, e.g. such as with the airr-tools merge program.

Fields Query Parameter

The fields parameter specifies which fields are to be included in the API response. By default all fields (AIRR and non-AIRR) stored in the data repository are returned. However, this can vary between data repositories based upon how the repository decides to store blank or null fields, so the fields and/or include_fields parameter should be used to guarantee the existence of data elements in the response.

Include Fields Query Parameter

The include_fields parameter specifies that the API response should include a well-defined set of AIRR Standard fields. These sets include:

  • miairr, for only the MiAIRR fields.

  • airr-core, for the AIRR required and identifier fields. This is expected to be the most common option as it provides all MiAIRR fields, additional required fields useful for analysis, and all identifier fields for linking objects in the AIRR Data Model.

  • airr-schema, for all AIRR fields in the AIRR Schema.

The include_fields parameter is a mechanism to ensure that specific AIRR data elements are returned without requiring those fields to be individually provided with the fields parameter. Any data elements that lack a value will be assigned null in the response. Any empty array of objects, for example subject.diagnosis, will be populated with a single object with all of the object’s properties given a null value. Any empty array of primitive data types, like string or number, will be assigned null. Note that if both the include_fields and the fields parameter are provided, the API response will include the set of AIRR fields and in addition will include any additional fields that are specified in the fields parameter.

Size and From Query Parameters

The ADC API provides a pagination feature that limits the number of results returned by the API.

The from query parameter specifies which record to start from when returning results. This allows records to be skipped. The default value is 0 indicating that the first record in the set of results will be returned.

The size query parameters specifies the maximum number of results to return. The default value is specific to the data repository, and a maximum value may be imposed by the data repository. This is to prevent queries from “accidently” returning millions of records. The info endpoint provides the data repository default and maximum values for the repertoire and rearrangement endpoints, which may have different values. A value of 0 indicates there is no limit on the number of results to return, but if the data repository does not support this then the default value will be used.

The combination of from and size can be used to implement pagination in a graphical user interface, or to split a very large download into smaller batches. For example, if an interface displays 10 records as a time, the request would assign size=10 and from=0 to get the ten results to display on the first page. When the user traverses to the “next page”, the request would assign from=10 to skip the first ten results and return the next ten results, and from=20 for the next page after that, and so on.

Facets Query Parameter

The facets parameter provides aggregate count information for the specified field. Only a single field can be specified. The facets parameter can be used in conjunction with the filters parameter to get aggregate counts for a set of search results. It returns the set of values for the field, and the number of records (repertoires or rearrangement) that have this value. For field values that have no counts, the API service can either return the field value with a 0 count or exclude the field value in the aggregation. The typical use of this parameter is for displaying aggregate information in a graphical user interface.

Here is a simple query with only the facets parameter to return the set of values for sample.pcr_target.pcr_target_locus and the count of repertoires repertoires that have each value. The content of the JSON payload.

{
    "facets":"sample.pcr_target.pcr_target_locus"
}

Sending this query in an API request.

curl --data @facets1_repertoire.json -H 'content-type: application/json' https://vdjserver.org/airr/v1/repertoire

The output from the request is similar to normal queries except the data is provided with the Facet key.

{
  "Info": {
    "title": "AIRR Data Commons API for VDJServer Community Data Portal",
    "description": "VDJServer ADC API response for repertoire query",
    "version": "1.3",
    "contact": {
      "name": "VDJServer",
      "url": "http://vdjserver.org/",
      "email": "vdjserver@utsouthwestern.edu"
    }
  },
  "Facet": [
    {
      "sample.pcr_target.pcr_target_locus": "TRB",
      "count": 2786
    },
    {
      "sample.pcr_target.pcr_target_locus": "TRA",
      "count": 242
    },
    {
      "sample.pcr_target.pcr_target_locus": "IGK",
      "count": 122
    },
    {
      "sample.pcr_target.pcr_target_locus": "IGH",
      "count": 547
    },
    {
      "sample.pcr_target.pcr_target_locus": "IGL",
      "count": 121
    }
  ]
}

Here is a query with both filters and facets parameters, which restricts the data records used for the facets count. The content of the JSON payload.

{
    "filters":{
        "op":"and",
        "content": [
            {
                "op":"=",
                "content": {
                    "field":"study.study_id",
                    "value":"PRJNA300878"
                }
            },
            {
                "op":"=",
                "content": {
                    "field":"sample.pcr_target.pcr_target_locus",
                    "value":"IGH"
                }
            }
        ]
    },
    "facets":"subject.subject_id"
}

Sending this query in an API request.

curl --data @facets2_repertoire.json -H 'content-type: application/json' https://vdjserver.org/airr/v1/repertoire

Example output from the request. This result indicates there are ten subjects each with two IGH repertoires.

{
  "Info": {
    "title": "AIRR Data Commons API reference implementation",
    "description": "API response for repertoire query",
    "version": 1.3,
    "contact": {
      "name": "AIRR Community",
      "url": "https://github.com/airr-community"
    }
  },
  "Facet": [
    {"subject.subject_id":"TW05B","count":2},
    {"subject.subject_id":"TW05A","count":2},
    {"subject.subject_id":"TW03A","count":2},
    {"subject.subject_id":"TW04A","count":2},
    {"subject.subject_id":"TW01A","count":2},
    {"subject.subject_id":"TW04B","count":2},
    {"subject.subject_id":"TW02A","count":2},
    {"subject.subject_id":"TW03B","count":2},
    {"subject.subject_id":"TW01B","count":2},
    {"subject.subject_id":"TW02B","count":2}
  ]
}

Queries on Nested Information#

As stated above, in general API response data will be have been flattened by the query handler. However, there are several instances in which properties within the top-level entities are arrays of objects, which cannot be flattened because all the information will be expected to present in the response. Therefore, in these cases, the data that is queried and potentially returned will be nested. In addition, while the array of object is obvious from the AIRR Schema, they array component does not appear in the hierarchical property names used by the API. Note that this does not create any collisions as the schema allows the existence of multiple properties with the same designation.

However, it results in two possible ways how an AND operator can behave when using such nested properties as input. These are defined as follows:

Given that two or more instances of an object class exists within an array that is a property of a higher-level entity, and given a query that contains an AND operation that uses tests on two or more properties of said object class as an input, the code handling the query will exhibit

  • local behavior, if for the AND operation to evaluate to TRUE it requires that all tests must succeed within an instance of the object and within at least one object of the array, i.e., the code is aware of the nesting and is able to parse the hierarchy of properties from the provided string, or

  • global behavior, if for the AND operation to evaluate to TRUE it requires all tests to succeed, but independent of the instances in which the matching properties are located, i.e., the code is agnostic to the nesting and treats all properties within the array as a single set.

While both behaviors have their use cases, ADC API handlers are expected to exhibit “local” behavior, as is easier to implement on the client-side, where it would require joining the the result sets of the queries for each of the properties individually.