Custom Queries

If need perform an advanced SQL, you can write some scripts SQL and access them by REST. These scripts are templates where you can pass by URL, values to them.

awesome_folder/example_of_powerful.read.sql:

1SELECT * FROM table WHERE name = "{{.field1}}" OR name = "{{.field2}}";

Get result:

GET /_QUERIES/awesome_folder/example_of_powerful?field1=foo&field2=bar

To activate it, you need configure a location to scripts in your prest.toml like:

[queries]
location = /path/to/queries/

Scripts templates rules

In your scripts, the fields to replace have to look like: field1 or field2 are examples

1SELECT * FROM table WHERE name = "{{.field1}}" OR name = "{{.field2}}";

Script file must have a suffix based on http verb:

HTTP Verb Suffix
GET .read.sql
POST .write.sql
PUT, PATCH .update.sql
DELETE .delete.sql

In queries.location, you need given a folder to your scripts:

 1queries/
 2└── foo
 3    └── some_get.read.sql
 4    └── some_create.write.sql
 5    └── some_update.update.sql
 6    └── some_delete.delete.sql
 7└── bar
 8    └── some_get.read.sql
 9    └── some_create.write.sql
10    └── some_update.update.sql
11    └── some_delete.delete.sql
12
13URLs to foo folder:
14
15GET    /_QUERIES/foo/some_get?field1=bar
16POST   /_QUERIES/foo/some_create?field1=bar
17PUT    /_QUERIES/foo/some_update?field1=bar
18PATCH  /_QUERIES/foo/some_update?field1=bar
19DELETE /_QUERIES/foo/some_delete?field1=bar
20
21
22URLs to bar folder:
23
24GET    /_QUERIES/bar/some_get?field1=foo
25POST   /_QUERIES/bar/some_create?field1=foo
26PUT    /_QUERIES/bar/some_update?field1=foo
27PATCH  /_QUERIES/bar/some_update?field1=foo
28DELETE /_QUERIES/bar/some_delete?field1=foo

Template data

You can access the query parameters of the incoming HTTP request using the . notation.

For instance, the following request:

GET    /_QUERIES/bar/some_get?field1=foo&field2=bar

makes available the fields field1 and field2 in the script:

{{.field1}}
{{.field2}}

You can also access the query headers of the incoming HTTP requests using the .header notation.

For instance, the following request:

GET    /_QUERIES/bar/some_get
X-UserId: am9obi5kb2VAYW5vbnltb3VzLmNvbQ
X-Application: prest

makes available the headers X-UserId and X-Application in the script:

{{index .header "X-UserId"}}
{{index .header "X-Application"}}

Template functions

isSet

Return true if param is set.

1SELECT * FROM table
2{{if isSet "field1"}}
3WHERE name = "{{.field1}}"
4{{end}}
5;

defaultOrValue

Return param value or default value.

1SELECT * FROM table WHERE name = '{{defaultOrValue "field1" "gopher"}}';

inFormat

If value of param is an slice this function format to an IN SQL clause.

1SELECT * FROM table WHERE name IN {{inFormat "field1"}};

split

Splits a string into substrings separated by a delimiter

1SELECT * FROM table WHERE
2name IN ({{ range $index,$part := split 'test1,test2,test3' `,` }}{{if gt $index 0 }},{{end}}'{{$part}}'{{ end }});

limitOffset

Assemble limit offset() string with validation for non-allowed characters parameters must be integer values

1SELECT * FROM table {{limitOffset "1" "10"}}

generating the query:

1SELECT * FROM table LIMIT 10 OFFSET(1 - 1) * 10

We recommend using the default pREST variables _page and _page_size:

1{{limitOffset ._page ._page_size}}

Ready-made queries

consultations ready to use prest