Обсуждение: JSON "pretty" and selecting nested JSON fields

On Mon, Mar 30, 2015 at 12:54 PM, Deven Phillips
<deven.phillips@gmail.com> wrote:
> Hi all,
>
>     I have a query which selects several rows of data, and contained in one
> of those rows is some aggregated JSON data. I am using row_to_json() to make
> the whole output JSON and I am providing "true" for pretty formatting of the
> JSON. The problem that I am seeing is that they nested JSON block is not
> being prettified along with the outer JSON.

It looks like a bug. The 'outer' to_json's pretty print feature should
control the whole structure IMO.  Personally, I think you'll have
better luck rigging another function to do whitespace insertion
formatting.

merlin

On 03/30/2015 10:54 AM, Deven Phillips wrote:
> Hi all,
>
>      I have a query which selects several rows of data, and contained in
> one of those rows is some aggregated JSON data. I am using row_to_json()
> to make the whole output JSON and I am providing "true" for pretty
> formatting of the JSON. The problem that I am seeing is that they nested
> JSON block is not being prettified along with the outer JSON.
>
> Example:
>
> I have a function which takes a single key param and returns a JSON array:
>
> CREATE OR REPLACE FUNCTION get_virtual_interfaces(vm_id BIGINT) RETURNS
> jsonb AS $$
> DECLARE
>      res jsonb;
> BEGIN
> SELECT array_to_json(array_agg(row_to_json(i, true)), true)
>          FROM (
>              SELECT DISTINCT * FROM virtual_interfaces WHERE vmid=vm_id)
> i INTO res;
>      RETURN res;
> END;
> $$ LANGUAGE PLPGSQL;
>
> That function is then used in another query to provide a nested JSON
> containing the array:
>
> SELECT
>      row.snt_code AS "snt_code",
>      row.vdc AS "vdc",
>      row.uuid AS "uuid",
>      row_to_json(row, true) AS "json"
> FROM (
>      SELECT
>          vm.*,
>          CONCAT('https://int.cloudcontrol.sgns.net/v3/customer/',
> vm.snt_code, '/vdc/', vm.vdc, '/vm/', vm.uuid) AS "self",
>          'cc.v3.sungardas.vm' AS "type",
>          (get_virtual_interfaces(vm.vmid)) as interfaces
>      FROM virtual_machines vm
> ) row;
>
> The outer level of JSON is "pretty printed", but the content of the
> array from the function is NOT, even though I have specified that it
> should be. Any suggestions of how to address this?

Well it is documented:

http://www.postgresql.org/docs/9.4/interactive/functions-json.html

row_to_json(record [, pretty_bool])     Returns the row as a JSON object.
Line feeds will be added between level-1 elements if
                                          ^^^^^^^
pretty_bool is true.

I would say post a feature request on --hackers or at ask if work is
being done on this.

>
> Thanks in advance!
>
> Deven


--
Adrian Klaver
adrian.klaver@aklaver.com

On Mon, Mar 30, 2015 at 3:30 PM, Adrian Klaver
<adrian.klaver@aklaver.com> wrote:
> On 03/30/2015 10:54 AM, Deven Phillips wrote:
>>
>> Hi all,
>>
>>      I have a query which selects several rows of data, and contained in
>> one of those rows is some aggregated JSON data. I am using row_to_json()
>> to make the whole output JSON and I am providing "true" for pretty
>> formatting of the JSON. The problem that I am seeing is that they nested
>> JSON block is not being prettified along with the outer JSON.
>>
>> Example:
>>
>> I have a function which takes a single key param and returns a JSON array:
>>
>> CREATE OR REPLACE FUNCTION get_virtual_interfaces(vm_id BIGINT) RETURNS
>> jsonb AS $$
>> DECLARE
>>      res jsonb;
>> BEGIN
>> SELECT array_to_json(array_agg(row_to_json(i, true)), true)
>>          FROM (
>>              SELECT DISTINCT * FROM virtual_interfaces WHERE vmid=vm_id)
>> i INTO res;
>>      RETURN res;
>> END;
>> $$ LANGUAGE PLPGSQL;
>>
>> That function is then used in another query to provide a nested JSON
>> containing the array:
>>
>> SELECT
>>      row.snt_code AS "snt_code",
>>      row.vdc AS "vdc",
>>      row.uuid AS "uuid",
>>      row_to_json(row, true) AS "json"
>> FROM (
>>      SELECT
>>          vm.*,
>>          CONCAT('https://int.cloudcontrol.sgns.net/v3/customer/',
>> vm.snt_code, '/vdc/', vm.vdc, '/vm/', vm.uuid) AS "self",
>>          'cc.v3.sungardas.vm' AS "type",
>>          (get_virtual_interfaces(vm.vmid)) as interfaces
>>      FROM virtual_machines vm
>> ) row;
>>
>> The outer level of JSON is "pretty printed", but the content of the
>> array from the function is NOT, even though I have specified that it
>> should be. Any suggestions of how to address this?
>
>
> Well it is documented:
>
> http://www.postgresql.org/docs/9.4/interactive/functions-json.html
>
> row_to_json(record [, pretty_bool])     Returns the row as a JSON object.
> Line feeds will be added between level-1 elements if
>                                          ^^^^^^^
> pretty_bool is true.
>
> I would say post a feature request on --hackers or at ask if work is being
> done on this.


Yeah, also, the OP's problem was made worse by using 'jsonb' inside
the function; jsonb ignores any whitespace formatting (as opposed to
json).

merlin