The Data Access API provides programmatic download access to the files stored under Dataverse. More advanced features of the Access API include format-specific transformations (thumbnail generation/resizing for images; converting tabular data into alternative file formats) and access to the data-level metadata that describes the contents of the tabular files.
Contents:
Basic access URI:
/api/access/datafile/$id
Note
Files can be accessed using persistent identifiers. This is done by passing the constant :persistentId where the numeric id of the file is expected, and then passing the actual persistent id as a query parameter with the name persistentId.
Example: Getting the file whose DOI is 10.5072/FK2/J8SJZB
GET http://$SERVER/api/access/datafile/:persistentId/?persistentId=doi:10.5072/FK2/J8SJZB
format
the following parameter values are supported (for tabular data files only):
| Value | Description |
|---|---|
| original | “Saved Original”, the proprietary (SPSS, Stata, R, etc.) file from which the tabular data was ingested; |
| RData | Tabular data as an R Data frame (generated; unless the “original” file was in R); |
| prep | “Pre-processed data”, in JSON. |
| subset | Column-wise subsetting. You must also supply a comma separated list of variables in the “variables” query parameter. In this example, 123 and 127 are the database ids of data variables that belong to the data file with the id 6: curl 'http://localhost:8080/api/access/datafile/6?format=subset&variables=123,127'. |
imageThumb
the following parameter values are supported (for image and pdf files only):
| Value | Description |
|---|---|
| true | Generates a thumbnail image, by rescaling to the default thumbnail size (64 pixels) |
N |
Rescales the image to N pixels. |
/api/access/datafiles/$id1,$id2,...$idN
Returns the files listed, zipped.
none.
/api/access/datafile/bundle/$id
This is convenience packaging method is available for tabular data files. It returns a zipped bundle that contains the data in the following formats:
none.
These methods are only available for tabular data files. (i.e., data files with associated data table and variable objects).
/api/access/datafile/$id/metadata/ddi
In its basic form the verb above returns a DDI fragment that describes the file and the data variables in it.
The DDI returned will only have two top-level sections:
fileDscr, with the basic file information plus the numbers of variables and observations and the UNF of the file.dataDscr section, with one var section for each variable.Example:
http://localhost:8080/api/access/datafile/6/metadata/ddi
<codeBook version="2.0">
<fileDscr ID="f6">
<fileTxt>
<fileName>_73084.tab</fileName>
<dimensns>
<caseQnty>3</caseQnty>
<varQnty>2</varQnty>
</dimensns>
<fileType>text/tab-separated-values</fileType>
</fileTxt>
<notes level="file" type="VDC:UNF" subject="Universal Numeric Fingerprint">UNF:6:zChnyI3fjwNP+6qW0VryVQ==</notes>
</fileDscr>
<dataDscr>
<var ID="v1" name="id" intrvl="discrete">
<location fileid="f6"/>
<labl level="variable">Personen-ID</labl>
<sumStat type="mean">2.0</sumStat>
<sumStat type="mode">.</sumStat>
<sumStat type="medn">2.0</sumStat>
<sumStat type="stdev">1.0</sumStat>
<sumStat type="min">1.0</sumStat>
<sumStat type="vald">3.0</sumStat>
<sumStat type="invd">0.0</sumStat>
<sumStat type="max">3.0</sumStat>
<varFormat type="numeric"/>
<notes subject="Universal Numeric Fingerprint" level="variable" type="VDC:UNF">UNF:6:AvELPR5QTaBbnq6S22Msow==</notes>
</var>
<var ID="v3" name="sex" intrvl="discrete">
<location fileid="f6"/>
<labl level="variable">Geschlecht</labl>
<sumStat type="mean">1.3333333333333333</sumStat>
<sumStat type="max">2.0</sumStat>
<sumStat type="vald">3.0</sumStat>
<sumStat type="mode">.</sumStat>
<sumStat type="stdev">0.5773502691896257</sumStat>
<sumStat type="invd">0.0</sumStat>
<sumStat type="medn">1.0</sumStat>
<sumStat type="min">1.0</sumStat>
<catgry>
<catValu>1</catValu>
<labl level="category">Mann</labl>
</catgry>
<catgry>
<catValu>2</catValu>
<labl level="category">Frau</labl>
</catgry>
<varFormat type="numeric"/>
<notes subject="Universal Numeric Fingerprint" level="variable" type="VDC:UNF">UNF:6:XqQaMwOA63taX1YyBzTZYQ==</notes>
</var>
</dataDscr>
</codeBook>
More information on DDI is available in the Tabular Data, Representation, Storage and Ingest section of the User Guide.
Advanced options/Parameters:
It is possible to request only specific subsets of, rather than the
full file-level DDI record. This can be a useful optimization, in
cases such as when an application needs to look up a single variable;
especially with data files with large numbers of variables. See
variables=123,127 in the example above.
/api/access/datafile/$id/metadata/preprocessed
This method provides the “preprocessed data” - a summary record that describes the values of the data vectors in the tabular file, in JSON. These metadata values are used by TwoRavens, the companion data exploration utility of the Dataverse application. Please note that this format might change in the future.
Data Access API supports both session- and API key-based authentication.
If a session is available, and it is already associated with an authenticated user, it will be used for access authorization. If not, or if the user in question is not authorized to access the requested object, an attempt will be made to authorize based on an API key, if supplied.
All of the API verbs above support the key parameter key=... as well as the newer X-Dataverse-key header. For more details, see “Authentication” in the Introduction section.