>
> On Tuesday, November 22, 2022 at 10:16:11 AM EST, Erik Wienhold <ewie@xxxxxxxxx> wrote:
>
>
> > On 22/11/2022 15:23 CET Alastair McKinley <a.mckinley@xxxxxxxxxxxxxxxxxxxx> wrote:
> >
> > Hi all,
> >
> > I have come across this apparently common issue COPY-ing json and wondering if
> > there is potentially a better solution.
> >
> > I am copying data into a jsonb column originating from a 3rd party API. The
> > data may have literal \r,\t,\n and also double backslashes.
> >
> > I discovered that I can cast this data to a jsonb value directly but I can't
> > COPY the data without pre-processing.
>
>
> > Is there any other solution with COPY that doesn't require manual
> > implementation of search/replace to handle these edge cases?
> > Why does ::jsonb work but COPY doesn't? It seems a bit inconsistent.
>
> COPY handles special backslash sequences[1]. The \r in your sample JSON,
> although properly escaped according to JSON, is replaced with an actual
> carriage return by COPY before casting to jsonb. The error results from JSON
> prohibiting unescaped control characters in strings[2].
>
> You must double escape to pass those characters through COPY.
>
> See how COPY outputs backslash sequences:
>
> -- Actual carriage return:
> copy (select e'\r') to stdout;
> \r
>
> -- Backslash sequence for carriage return:
> copy (select '\r') to stdout;
>
> On Tuesday, November 22, 2022 at 10:16:11 AM EST, Erik Wienhold <ewie@xxxxxxxxx> wrote:
>
>
> > On 22/11/2022 15:23 CET Alastair McKinley <a.mckinley@xxxxxxxxxxxxxxxxxxxx> wrote:
> >
> > Hi all,
> >
> > I have come across this apparently common issue COPY-ing json and wondering if
> > there is potentially a better solution.
> >
> > I am copying data into a jsonb column originating from a 3rd party API. The
> > data may have literal \r,\t,\n and also double backslashes.
> >
> > I discovered that I can cast this data to a jsonb value directly but I can't
> > COPY the data without pre-processing.
>
>
> > Is there any other solution with COPY that doesn't require manual
> > implementation of search/replace to handle these edge cases?
> > Why does ::jsonb work but COPY doesn't? It seems a bit inconsistent.
>
> COPY handles special backslash sequences[1]. The \r in your sample JSON,
> although properly escaped according to JSON, is replaced with an actual
> carriage return by COPY before casting to jsonb. The error results from JSON
> prohibiting unescaped control characters in strings[2].
>
> You must double escape to pass those characters through COPY.
>
> See how COPY outputs backslash sequences:
>
> -- Actual carriage return:
> copy (select e'\r') to stdout;
> \r
>
> -- Backslash sequence for carriage return:
> copy (select '\r') to stdout;
>
> \\r
I have been able to get around this problem by using the following method:
\copy footable from 'input.json' (format csv, escape '^B', delimieter '^C', quote '^E')
where the control characters are the actual control char, not the caret-letter, and it requires no escaping escapes. I realize this won't work for all
>
> [1]
> https://www.postgresql.org/docs/current/sql-copy.html#id-1.9.3.55.9.2
> [2] https://www.json.org/json-en.html
>
> --
> Erik
\copy footable from 'input.json' (format csv, escape '^B', delimieter '^C', quote '^E')
where the control characters are the actual control char, not the caret-letter, and it requires no escaping escapes. I realize this won't work for all
situations.
PJ
>
> [1]
> https://www.postgresql.org/docs/current/sql-copy.html#id-1.9.3.55.9.2
> [2] https://www.json.org/json-en.html
>
> --
> Erik
