jimmy/postgrest
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity
Files
dbec5e08aa29c43eafb608f54ec2768defabd9d4
postgrest/api.rst
T

842 lines
35 KiB
ReStructuredText
Raw Blame History

This file contains ambiguous Unicode characters
This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.
.. role:: sql(code)
:language: sql
Tables and Views
================
All views and tables in the active schema and accessible by the active database role for a request are available for querying. They are exposed in one-level deep routes. For instance the full contents of a table `people` is returned at
.. code-block:: http
GET /people HTTP/1.1
There are no deeply/nested/routes. Each route provides OPTIONS, GET, POST, PATCH, and DELETE verbs depending entirely on database permissions.
.. note::
Why not provide nested routes? Many APIs allow nesting to retrieve related information, such as :code:`/films/1/director`. We offer a more flexible mechanism (inspired by GraphQL) to embed related information. It can handle one-to-many and many-to-many relationships. This is covered in the section about :ref:`resource_embedding`.
.. _h_filter:
Horizontal Filtering (Rows)
---------------------------
You can filter result rows by adding conditions on columns, each condition a query string parameter. For instance, to return people aged under 13 years old:
.. code-block:: http
GET /people?age=lt.13 HTTP/1.1
Multiple parameters can be logically conjoined by:
.. code-block:: http
GET /people?age=gte.18&student=is.true HTTP/1.1
Multiple parameters can be logically disjoined by:
.. code-block:: http
GET /people?or=(age.gte.14,age.lte.18) HTTP/1.1
Complex logic can also be applied:
.. code-block:: http
GET /people?and=(grade.gte.90,student.is.true,or(age.gte.14,age.is.null)) HTTP/1.1
These operators are available:
============ =============================================== =====================
Abbreviation Meaning PostgreSQL Equivalent
============ =============================================== =====================
eq equals :code:`=`
gt greater than :code:`>`
gte greater than or equal :code:`>=`
lt less than :code:`<`
lte less than or equal :code:`<=`
neq not equal :code:`<>` or :code:`!=`
like LIKE operator (use * in place of %) :code:`LIKE`
ilike ILIKE operator (use * in place of %) :code:`ILIKE`
in one of a list of values e.g. :code:`IN`
:code:`?a=in.(1,2,3)` – also supports commas
in quoted strings like
:code:`?a=in.("hi,there","yes,you")`
is checking for exact equality (null,true,false) :code:`IS`
fts :ref:`fts` using to_tsquery :code:`@@`
plfts :ref:`fts` using plainto_tsquery :code:`@@`
phfts :ref:`fts` using phraseto_tsquery :code:`@@`
cs contains e.g. :code:`?tags=cs.{example, new}` :code:`@>`
cd contained in e.g. :code:`?values=cd.{1,2,3}` :code:`<@`
ov overlap (have points in common), :code:`&&`
e.g. :code:`?period=ov.[2017-01-01,2017-06-30]`
sl strictly left of, e.g. :code:`?range=sl.(1,10)` :code:`<<`
sr strictly right of :code:`>>`
nxr does not extend to the right of, :code:`&<`
e.g. :code:`?range=nxr.(1,10)`
nxl does not extend to the left of :code:`&>`
adj is adjacent to, e.g. :code:`?range=adj.(1,10)` :code:`-|-`
not negates another operator, see below :code:`NOT`
============ =============================================== =====================
.. note::
As of PostgREST v0.4.3.0, the symbol operators :code:`@@, @>, <@` have been
deprecated in lieu of their mnemonic equivalents. They are still supported
but will be removed in v0.5.0.0.
To negate any operator, prefix it with :code:`not` like :code:`?a=not.eq.2` or :code:`?not.and=(a.gte.0,a.lte.100)` .
For more complicated filters you will have to create a new view in the database, or use a stored procedure. For instance, here's a view to show "today's stories" including possibly older pinned stories:
.. code-block:: postgresql
CREATE VIEW fresh_stories AS
SELECT *
FROM stories
WHERE pinned = true
OR published > now() - interval '1 day'
ORDER BY pinned DESC, published DESC;
The view will provide a new endpoint:
.. code-block:: http
GET /fresh_stories HTTP/1.1
.. _fts:
Full-Text Search
~~~~~~~~~~~~~~~~
The :code:`fts` filter mentioned above has a number of options to support flexible textual queries, namely the choice of plain vs phrase search and the language used for stemming. Suppose that :code:`tsearch` is a table with column :code:`my_tsv`, of type `tsvector <https://www.postgresql.org/docs/current/static/datatype-textsearch.html>`_. The follow examples illustrate the possibilities.
.. code-block:: http
# Use language in fts query
GET /tsearch?my_tsv=fts(french).amusant
# Use plainto_tsquery and phraseto_tsquery
GET /tsearch?my_tsv=plfts.The%20Fat%20Cats
GET /tsearch?my_tsv=phfts.The%20Fat%20Rats
# Combine both
GET /tsearch?my_tsv=phfts(english).The%20Fat%20Cats
# "not" also working
GET /tsearch?my_tsv=not.phfts(english).The%20Fat%20Cats
Using phrase search mode requires PostgreSQL of version at least 9.6 and will raise an error in earlier versions of the database.
.. _v_filter:
Vertical Filtering (Columns)
----------------------------
When certain columns are wide (such as those holding binary data), it is more efficient for the server to withhold them in a response. The client can specify which columns are required using the :sql:`select` parameter.
.. code-block:: http
GET /people?select=fname,age HTTP/1.1
The default is :sql:`*`, meaning all columns. This value will become more important below in :ref:`resource_embedding`.
.. _computed_cols:
Computed Columns
~~~~~~~~~~~~~~~~
Filters may be applied to computed columns as well as actual table/view columns, even though the computed columns will not appear in the output. For example, to search first and last names at once we can create a computed column that will not appear in the output but can be used in a filter:
.. code-block:: postgres
CREATE TABLE people (
fname text,
lname text
);
CREATE FUNCTION full_name(people) RETURNS text AS $$
SELECT $1.fname || ' ' || $1.lname;
$$ LANGUAGE SQL;
-- (optional) add an index to speed up anticipated query
CREATE INDEX people_full_name_idx ON people
USING GIN (to_tsvector('english', full_name(people)));
A full-text search on the computed column:
.. code-block:: http
GET /people?full_name=fts.Beckett HTTP/1.1
As mentioned, computed columns do not appear in the output by default. However you can include them by listing them in the vertical filtering :code:`select` param:
.. code-block:: HTTP
GET /people?select=*,full_name HTTP/1.1
Ordering
--------
The reserved word :sql:`order` reorders the response rows. It uses a comma-separated list of columns and directions:
.. code-block:: http
GET /people?order=age.desc,height.asc HTTP/1.1
If no direction is specified it defaults to ascending order:
.. code-block:: http
GET /people?order=age HTTP/1.1
If you care where nulls are sorted, add nullsfirst or nullslast:
.. code-block:: http
GET /people?order=age.nullsfirst HTTP/1.1
.. code-block:: http
GET /people?order=age.desc.nullslast HTTP/1.1
You can also use :ref:`computed_cols` to order the results, even though the computed columns will not appear in the output.
.. _limits:
Limits and Pagination
---------------------
PostgREST uses HTTP range headers to describe the size of results. Every response contains the current range and, if requested, the total number of results:
.. code-block:: http
HTTP/1.1 200 OK
Range-Unit: items
Content-Range: 0-14/*
Here items zero through fourteen are returned. This information is available in every response and can help you render pagination controls on the client. This is an RFC7233-compliant solution that keeps the response JSON cleaner.
There are two ways to apply a limit and offset rows: through request headers or query params. When using headers you specify the range of rows desired. This request gets the first twenty people.
.. code-block:: http
GET /people HTTP/1.1
Range-Unit: items
Range: 0-19
Note that the server may respond with fewer if unable to meet your request:
.. code-block:: http
HTTP/1.1 200 OK
Range-Unit: items
Content-Range: 0-17/*
You may also request open-ended ranges for an offset with no limit, e.g. :code:`Range: 10-`.
The other way to request a limit or offset is with query parameters. For example
.. code-block:: http
GET /people?limit=15&offset=30 HTTP/1.1
This method is also useful for embedded resources, which we will cover in another section. The server always responds with range headers even if you use query parameters to limit the query.
In order to obtain the total size of the table or view (such as when rendering the last page link in a pagination control), specify your preference in a request header:
.. code-block:: http
GET /bigtable HTTP/1.1
Range-Unit: items
Range: 0-24
Prefer: count=exact
Note that the larger the table the slower this query runs in the database. The server will respond with the selected range and total
.. code-block:: http
HTTP/1.1 206 Partial Content
Range-Unit: items
Content-Range: 0-24/3573458
Response Format
---------------
PostgREST uses proper HTTP content negotiation (`RFC7231 <https://tools.ietf.org/html/rfc7231#section-5.3>`_) to deliver the desired representation of a resource. That is to say the same API endpoint can respond in different formats like JSON or CSV depending on the client request.
Use the Accept request header to specify the acceptable format (or formats) for the response:
.. code-block:: http
GET /people HTTP/1.1
Accept: application/json
The current possibilities are
* \*/\*
* text/csv
* application/json
* application/openapi+json
* application/octet-stream
The server will default to JSON for API endpoints and OpenAPI on the root.
.. _singular_plural:
Singular or Plural
------------------
By default PostgREST returns all JSON results in an array, even when there is only one item. For example, requesting :code:`/items?id=eq.1` returns
.. code:: json
[
{ "id": 1 }
]
This can be inconvenient for client code. To return the first result as an object unenclosed by an array, specify :code:`vnd.pgrst.object` as part of the :code:`Accept` header
.. code:: http
GET /items?id=eq.1 HTTP/1.1
Accept: application/vnd.pgrst.object+json
This returns
.. code:: json
{ "id": 1 }
When a singular response is requested but no entries are found, the server responds with an error message and 406 Not Acceptable status code rather than the usual empty array and 200 status:
.. code-block:: json
{
"message": "JSON object requested, multiple (or no) rows returned",
"details": "Results contain 0 rows, application/vnd.pgrst.object+json requires 1 row"
}
.. note::
Many APIs distinguish plural and singular resources using a special nested URL convention e.g. `/stories` vs `/stories/1`. Why do we use `/stories?id=eq.1`? The answer is because a singular resource is (for us) a row determined by a primary key, and primary keys can be compound (meaning defined across more than one column). The more familiar nested urls consider only a degenerate case of simple and overwhelmingly numeric primary keys. These so-called artificial keys are often introduced automatically by Object Relational Mapping libraries.
Admittedly PostgREST could detect when there is an equality condition holding on all columns constituting the primary key and automatically convert to singular. However this could lead to a surprising change of format that breaks unwary client code just by filtering on an extra column. Instead we allow manually specifying singular vs plural to decouple that choice from the URL format.
Binary output
-------------
If you want to return raw binary data from a :code:`bytea` column, you must specify :code:`application/octet-stream` as part of the :code:`Accept` header
and select a single column :code:`?select=bin_data`.
.. code:: http
GET /items?select=bin_data&id=eq.1 HTTP/1.1
Accept: application/octet-stream
You can also request binary output when calling stored procedures and since they can return a scalar value you are not forced to use :code:`select`
for this case.
.. code:: sql
CREATE FUNCTION closest_point(..) RETURNS bytea ..
.. code:: http
POST /rpc/closest_point HTTP/1.1
Accept: application/octet-stream
If the stored procedure returns non-scalar values, you need to do a :code:`select` in the same way as for GET binary output.
.. code:: sql
CREATE FUNCTION overlapping_regions(..) RETURNS SETOF TABLE(geom_twkb bytea, ..) ..
.. code:: http
POST /rpc/overlapping_regions?select=geom_twkb HTTP/1.1
Accept: application/octet-stream
.. note::
If more than one row would be returned the binary results will be concatenated with no delimiter.
Unicode Support
===============
PostgREST supports unicode in schemas, tables, columns and values. To access a table with unicode name, use percent encoding.
To request this:
.. code-block:: html
http://localhost:3000/موارد
Do this:
.. code-block:: html
http://localhost:3000/%D9%85%D9%88%D8%A7%D8%B1%D8%AF
.. _resource_embedding:
Resource Embedding
==================
In addition to providing RESTful routes for each table and view, PostgREST allows related resources to be included together in a single API call. This reduces the need for multiple API requests. The server uses foreign keys to determine which tables and views can be returned together. For example, consider a database of films and their awards:
.. image:: _static/film.png
As seen above in :ref:`v_filter` we can request the titles of all films like this:
.. code-block:: http
GET /films?select=title HTTP/1.1
This might return something like
.. code-block:: json
[
{ "title": "Workers Leaving The Lumière Factory In Lyon" },
{ "title": "The Dickson Experimental Sound Film" },
{ "title": "The Haunted Castle" }
]
However because a foreign key constraint exists between Films and Directors, we can request this information be included:
.. code-block:: http
GET /films?select=title,directors(id,last_name) HTTP/1.1
Which would return
.. code-block:: json
[
{ "title": "Workers Leaving The Lumière Factory In Lyon",
"directors": {
"id": 2,
"last_name": "Lumière"
}
},
{ "title": "The Dickson Experimental Sound Film",
"directors": {
"id": 1,
"last_name": "Dickson"
}
},
{ "title": "The Haunted Castle",
"directors": {
"id": 3,
"last_name": "Méliès"
}
}
]
In this example, since the relationship is a forward relationship, there is
only one director associated with a film. As the table name is plural it might
be preferable for it to be singular instead. An table name alias can accomplish
this:
.. code-block:: http
GET /films?select=title,director:directors(id,last_name) HTTP/1.1
.. note::
As of PostgREST v0.4.1.0, parens :code:`()` are used rather than brackets :code:`{}` for the list of embedded columns. Brackets are still supported, but are deprecated and will be removed in v0.5.0.0.
PostgREST can also detect relations going through join tables. Thus you can request the Actors for Films (which in this case finds the information through Roles). You can also reverse the direction of inclusion, asking for all Directors with each including the list of their Films:
.. code-block:: http
GET /directors?select=films(title,year) HTTP/1.1
.. note::
Whenever foreign key relations change in the database schema you must refresh PostgREST's schema cache to allow resource embedding to work properly. See the section :ref:`schema_reloading`.
Embedded Filters and Order
--------------------------
Embedded tables can be filtered and ordered similarly to their top-level counterparts. To do so, prefix the query parameters with the name of the embedded table. For instance, to order the actors in each film:
.. code-block:: http
GET /films?select=*,actors(*)&actors.order=last_name,first_name HTTP/1.1
This sorts the list of actors in each film but does *not* change the order of the films themselves. To filter the roles returned with each film:
.. code-block:: http
GET /films?select=*,roles(*)&roles.character=in.(Chico,Harpo,Groucho) HTTP/1.1
Once again, this restricts the roles included to certain characters but does not filter the films in any way. Films without any of those characters would be included along with empty character lists.
Custom Queries
==============
The PostgREST URL grammar limits the kinds of queries clients can perform. It prevents arbitrary, potentially poorly constructed and slow client queries. It's good for quality of service, but means database administrators must create custom views and stored procedures to provide richer endpoints. The most common causes for custom endpoints are
* Table unions
* More complicated joins than those provided by `Resource Embedding`_
* Geo-spatial queries that require an argument, like "points near (lat,lon)"
* More sophisticated full-text search than a simple use of the :sql:`fts` filter
Stored Procedures
=================
Every stored procedure in the API-exposed database schema is accessible under the :code:`/rpc` prefix. The API endpoint supports POST (and in some cases GET) to execute the function.
.. code:: http
POST /rpc/function_name HTTP/1.1
Such functions can perform any operations allowed by PostgreSQL (read data, modify data, and even DDL operations). However procedures in PostgreSQL marked with :code:`stable` or :code:`immutable` `volatility <https://www.postgresql.org/docs/current/static/xfunc-volatility.html>`_ can only read, not modify, the database and PostgREST executes them in a read-only transaction compatible for read-replicas. Stable and immutable functions can be called with the HTTP GET verb if desired.
Procedures must be used with `named arguments <https://www.postgresql.org/docs/current/static/sql-syntax-calling-funcs.html#SQL-SYNTAX-CALLING-FUNCS-NAMED>`_. To supply arguments in an API call, include a JSON object in the request payload and each key/value of the object will become an argument.
For instance, assume we have created this function in the database.
.. code:: plpgsql
CREATE FUNCTION add_them(a integer, b integer)
RETURNS integer AS $$
SELECT $1 + $2;
$$ LANGUAGE SQL IMMUTABLE STRICT;
The client can call it by posting an object like
.. code:: http
POST /rpc/add_them HTTP/1.1
{ "a": 1, "b": 2 }
Because ``add_them`` is declared IMMUTABLE, we can alternately call the function with a GET request:
.. code:: http
GET /rpc/add_them?a=1&b=2 HTTP/1.1
For POST and GET the keys of the object match the parameter names. Note that PostgreSQL converts parameter names to lowercase unless you quote them like :sql:`CREATE FUNCTION foo("mixedCase" text) ...`. You can also call a function that takes a single parameter of type json by sending the header :code:`Prefer: params=single-object` with your request. That way the JSON request body will be used as the single argument.
.. note::
We recommend using function arguments of type json to accept arrays from the client. To pass a PostgreSQL native array you'll need to quote it as a string:
.. code:: http
POST /rpc/native_array_func HTTP/1.1
{ "arg": "{1,2,3}" }
.. code:: http
POST /rpc/json_array_func HTTP/1.1
{ "arg": [1,2,3] }
PostgreSQL has four procedural languages that are part of the core distribution: PL/pgSQL, PL/Tcl, PL/Perl, and PL/Python. There are many other procedural languages distributed as additional extensions. Also, plain SQL can be used to write functions (as shown in the example above).
By default, a function is executed with the privileges of the user who calls it. This means that the user has to have all permissions to do the operations the procedure performs. Another option is to define the function with with the :code:`SECURITY DEFINER` option. Then only one permission check will take place, the permission to call the function, and the operations in the function will have the authority of the user who owns the function itself. See `PostgreSQL documentation <https://www.postgresql.org/docs/current/static/sql-createfunction.html>`_ for more details.
.. note::
Why the `/rpc` prefix? One reason is to avoid name collisions between views and procedures. It also helps emphasize to API consumers that these functions are not normal restful things. The functions can have arbitrary and surprising behavior, not the standard "post creates a resource" thing that users expect from the other routes.
Accessing Request Headers/Cookies
---------------------------------
Stored procedures can access request headers and cookies by reading GUC variables set by PostgREST per request. They are named :code:`request.header.XYZ` and :code:`request.cookie.XYZ`. For example, to read the value of the Origin request header:
.. code-block:: postgresql
SELECT current_setting('request.header.origin', true);
Errors and HTTP Status Codes
----------------------------
Stored procedures can return non-200 HTTP status codes by raising SQL exceptions. For instance, here's a saucy function that always responds with an error:
.. code-block:: postgresql
CREATE OR REPLACE FUNCTION just_fail() RETURNS void
LANGUAGE plpgsql
AS $$
BEGIN
RAISE EXCEPTION 'I refuse!'
USING DETAIL = 'Pretty simple',
HINT = 'There is nothing you can do.';
END
$$;
Calling the function returns HTTP 400 with the body
.. code-block:: json
{
"message":"I refuse!",
"details":"Pretty simple",
"hint":"There is nothing you can do.",
"code":"P0001"
}
One way to customize the HTTP status code is by raising particular exceptions according to the PostgREST :ref:`error to status code mapping <status_codes>`. For example, :code:`RAISE insufficient_privilege` will respond with HTTP 401/403 as appropriate.
For even greater control of the HTTP status code, raise an exception of the ``PTxyz`` type. For instance to respond with HTTP 402, raise 'PT402':
.. code-block:: sql
RAISE sqlstate 'PT402' using
message = 'Payment Required',
detail = 'Quota exceeded',
hint = 'Upgrade your plan';
Returns:
.. code-block:: http
HTTP/1.1 402 Payment Required
Content-Type: application/json; charset=utf-8
{"hint":"Upgrade your plan","details":"Quota exceeded"}
Setting Response Headers
------------------------
PostgREST reads the ``response.headers`` SQL variable to add extra headers to the HTTP response. Stored procedures can modify this variable. For instance, this statement would add caching headers to the response:
.. code-block:: sql
-- tell client to cache response for two days
SET LOCAL "response.headers" =
'[{"Cache-Control": "public"}, {"Cache-Control": "max-age=259200"}]';
Notice that the variable should be set to an *array* of single-key objects rather than a single multiple-key object. This is because headers such as ``Cache-Control`` or ``Set-Cookie`` need to be repeated when setting multiple values and an object would not allow the repeated key.
Insertions / Updates
====================
All tables and `auto-updatable views <https://www.postgresql.org/docs/current/static/sql-createview.html#SQL-CREATEVIEW-UPDATABLE-VIEWS>`_ can be modified through the API, subject to permissions of the requester's database role.
To create a row in a database table post a JSON object whose keys are the names of the columns you would like to create. Missing properties will be set to default values when applicable.
.. code:: HTTP
POST /table_name HTTP/1.1
{ "col1": "value1", "col2": "value2" }
The response will include a :code:`Location` header describing where to find the new object. If the table is write-only then constructing the Location header will cause a permissions error. To successfully insert an item to a write-only table you will need to suppress the Location response header by including the request header :code:`Prefer: return=minimal`.
On the other end of the spectrum you can get the full created object back in the response to your request by including the header :code:`Prefer: return=representation`. That way you won't have to make another HTTP call to discover properties that may have been filled in on the server side. You can also apply the standard :ref:`v_filter` to these results.
.. note::
When inserting a row you must post a JSON object, not quoted JSON.
.. code::
Yes
{ "a": 1, "b": 2 }
No
"{ \"a\": 1, \"b\": 2 }"
Some javascript libraries will post the data incorrectly if you're not careful. For best results try one of the :ref:`clientside_libraries` built for PostgREST.
To update a row or rows in a table, use the PATCH verb. Use :ref:`h_filter` to specify which record(s) to update. Here is an example query setting the :code:`category` column to child for all people below a certain age.
.. code:: HTTP
PATCH /people?age=lt.13 HTTP/1.1
{ "category": "child" }
Updates also support :code:`Prefer: return=representation` plus :ref:`v_filter`.
.. note::
Beware of accidentally updating every row in a table. To learn to prevent that see :ref:`block_fulltable`.
Bulk Insert
-----------
Bulk insert works exactly like single row insert except that you provide either a JSON array of objects having uniform keys, or lines in CSV format. This not only minimizes the HTTP requests required but uses a single INSERT statement on the back-end for efficiency. Note that using CSV requires less parsing on the server and is much faster.
To bulk insert CSV simply post to a table route with :code:`Content-Type: text/csv` and include the names of the columns as the first row. For instance
.. code:: HTTP
POST /people HTTP/1.1
Content-Type: text/csv
name,age,height
J Doe,62,70
Jonas,10,55
An empty field (:code:`,,`) is coerced to an empty string and the reserved word :code:`NULL` is mapped to the SQL null value. Note that there should be no spaces between the column names and commas.
To bulk insert JSON post an array of objects having all-matching keys
.. code:: HTTP
POST /people HTTP/1.1
Content-Type: application/json
[
{ "name": "J Doe", "age": 62, "height": 70 },
{ "name": "Janus", "age": 10, "height": 55 }
]
Upsert
------
You can make an UPSERT with :code:`POST` and the :code:`Prefer: resolution=merge-duplicates` header:
.. code:: HTTP
POST /employees HTTP/1.1
Prefer: resolution=merge-duplicates
[
{ "id": 1, "name": "Old employee 1", "salary": 30000 },
{ "id": 2, "name": "Old employee 2" , "salary": 42000 },
{ "id": 3, "name": "New employee 3" , "salary": 50000 }
]
UPSERT merging operates based on the primary key columns, you must specify all of them. You can also choose to ignore the duplicates with :code:`Prefer: resolution=ignore-duplicates`.
A single row UPSERT can be done by using :code:`PUT` and filtering the primary key columns with :code:`eq`:
.. code:: HTTP
PUT /employees?id=eq.4 HTTP/1.1
{ "id": 4, "name": "Sara B.", "salary": 60000 }
All the columns must be specified in the request body, including the primary key columns.
.. note::
This feature is only available starting from PostgreSQL 9.5 since it uses the `ON CONFLICT clause <https://www.postgresql.org/docs/9.5/static/sql-insert.html#SQL-ON-CONFLICT>`_.
Deletions
=========
To delete rows in a table, use the DELETE verb plus :ref:`h_filter`. For instance deleting inactive users:
.. code-block:: HTTP
DELETE /user?active=is.false HTTP/1.1
.. note::
Beware of accidentally deleting all rows in a table. To learn to prevent that see :ref:`block_fulltable`.
OpenAPI Support
===============
Every API hosted by PostgREST automatically serves a full `OpenAPI <https://www.openapis.org/>`_ description on the root path. This provides a list of all endpoints(tables, foreign tables, views, functions), along with supported HTTP verbs and example payloads. For extra customization, the OpenAPI output contains a "description" field for every `SQL comment <https://www.postgresql.org/docs/current/static/sql-comment.html>`_ on any database object. For instance,
.. code-block:: sql
COMMENT ON SCHEMA mammals IS
'A warm-blooded vertebrate animal of a class that is distinguished by the secretion of milk by females for the nourishment of the young';
COMMENT ON TABLE monotremes IS
'Freakish mammals lay the best eggs for breakfast';
COMMENT ON COLUMN monotremes.has_venomous_claw IS
'Sometimes breakfast is not worth it';
These unsavory comments will appear in the generated JSON as the fields, ``info.description``, ``definitions.monotremes.description`` and ``definitions.monotremes.properties.has_venomous_claw.description``.
Also if you wish to generate a ``summary`` field you can do it by having a multiple line comment, the ``summary`` will be the first line and the ``description`` the lines that follow it:
.. code-block:: sql
COMMENT ON TABLE entities IS
$$Entities summary
Entities description that
spans
multiple lines$$;
You can use a tool like `Swagger UI <http://swagger.io/swagger-ui/>`_ to create beautiful documentation from the description and to host an interactive web-based dashboard. The dashboard allows developers to make requests against a live PostgREST server, and provides guidance with request headers and example request bodies.
.. note::
The OpenAPI information can go out of date as the schema changes under a running server. To learn how to refresh the cache see :ref:`schema_reloading`.
.. _status_codes:
HTTP Status Codes
=================
PostgREST translates `PostgreSQL error codes <https://www.postgresql.org/docs/current/static/errcodes-appendix.html>`_ into HTTP status as follows:
+--------------------------+-------------------------+---------------------------------+
| PostgreSQL error code(s) | HTTP status | Error description |
+==========================+=========================+=================================+
| 08* | 503 | pg connection err |
+--------------------------+-------------------------+---------------------------------+
| 09* | 500 | triggered action exception |
+--------------------------+-------------------------+---------------------------------+
| 0L* | 403 | invalid grantor |
+--------------------------+-------------------------+---------------------------------+
| 0P* | 403 | invalid role specification |
+--------------------------+-------------------------+---------------------------------+
| 23503 | 409 | foreign key violation |
+--------------------------+-------------------------+---------------------------------+
| 23505 | 409 | uniqueness violation |
+--------------------------+-------------------------+---------------------------------+
| 25* | 500 | invalid transaction state |
+--------------------------+-------------------------+---------------------------------+
| 28* | 403 | invalid auth specification |
+--------------------------+-------------------------+---------------------------------+
| 2D* | 500 | invalid transaction termination |
+--------------------------+-------------------------+---------------------------------+
| 38* | 500 | external routine exception |
+--------------------------+-------------------------+---------------------------------+
| 39* | 500 | external routine invocation |
+--------------------------+-------------------------+---------------------------------+
| 3B* | 500 | savepoint exception |
+--------------------------+-------------------------+---------------------------------+
| 40* | 500 | transaction rollback |
+--------------------------+-------------------------+---------------------------------+
| 53* | 503 | insufficient resources |
+--------------------------+-------------------------+---------------------------------+
| 54* | 413 | too complex |
+--------------------------+-------------------------+---------------------------------+
| 55* | 500 | obj not in prerequisite state |
+--------------------------+-------------------------+---------------------------------+
| 57* | 500 | operator intervention |
+--------------------------+-------------------------+---------------------------------+
| 58* | 500 | system error |
+--------------------------+-------------------------+---------------------------------+
| F0* | 500 | conf file error |
+--------------------------+-------------------------+---------------------------------+
| HV* | 500 | foreign data wrapper error |
+--------------------------+-------------------------+---------------------------------+
| P0001 | 400 | default code for "raise" |
+--------------------------+-------------------------+---------------------------------+
| P0* | 500 | PL/pgSQL error |
+--------------------------+-------------------------+---------------------------------+
| XX* | 500 | internal error |
+--------------------------+-------------------------+---------------------------------+
| 42883 | 404 | undefined function |
+--------------------------+-------------------------+---------------------------------+
| 42P01 | 404 | undefined table |
+--------------------------+-------------------------+---------------------------------+
| 42501 | | if authenticated 403, | insufficient privileges |
| | | else 401 | |
+--------------------------+-------------------------+---------------------------------+
| other | 500 | |
+--------------------------+-------------------------+---------------------------------+
Reference in New Issue View Git Blame Copy Permalink