nginx + PostgreSQL：返回JSON对象

Question

I like to run a PostgreSQL 10 server as a backend and nginx with ngx_postgres as a frontend. The database stores data in JSONB format:

=# CREATE TABLE dump (
   id   bigserial primary key,
   data jsonb     not null
);

The data can be queried like:

=# SELECT data FROM dump;

Using ngx_postgres, one can access the PostgreSQL database directly from nginx:

upstream postgresql {
    postgres_server localhost dbname=default user=user password=secret;
}

server {
    listen 80;

    location /postgresql/ {
        rds_json          on;

        postgres_pass     postgresql;
        postgres_query    HEAD GET "SELECT data FROM dump"
        postgres_rewrite  no_rows 410;
        postgres_output   rds;
    }
}

But the result is returned as text, with escaped double quotes, not JSON as intended:

[{"data":"{\"id\": \"00ce160e5cbb49b9bc2ee6f243f87841\", \"name\": \"foo\"}"}] 

How can I return the result of the query as an JSON object?

Answer 1

You can try the c2h5oh framework. It is a fast and lightweight framework for building web applications using power of Nginx and PostgresSQL

https://github.com/genosse/c2h5oh/

Answer 2

After several attempts I was able to output JSON by changing the nginx configuration. The nginx module headers-more has to be installed and loaded for this to work:

server {
    listen 80;

    location /postgresql/ {
        rds_json          off;

        postgres_pass     postgresql;
        postgres_query    HEAD GET "SELECT json_agg(data) FROM dump"
        postgres_rewrite  no_rows 410;
        postgres_output   text;
        more_set_headers  'content-type: application/json';
    }
}

First, the PostgreSQL output format has to be set to text . Then, the default content type must be overridden with more_set_headers . The result served by nginx is valid JSON.