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Date: Mon, 22 Apr 2024 09:57:10 -0700
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Subject: Re: Safe SELECT ... LIKE abc% in psycopg
From: Adrian Klaver <adrian.klaver@aklaver.com>
To: Philippe Strauss <philippe@straussaudio.ch>, psycopg@lists.postgresql.org
References: <6b4e2581-8b08-4f0c-b159-cd078fd988a9@straussaudio.ch>
 <387a4f5e-5886-443d-bc4e-e649706173a4@aklaver.com>
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On 4/22/24 09:50, Adrian Klaver wrote:
> On 4/22/24 09:34, Philippe Strauss wrote:
>> Hello, I'm Philippe from switzerland,
>>
>> I'm writing using python a small JSON API for a mycology photos 
>> archive webapp. Aside the main API endpoint are two
>> helpers for an autocomplete form.
>> Here is the first one:
>>
>> --8<--
>> @app.route('/genus/<genus>')
>> def genus(genus):
>>      with dbconn.cursor() as cur:
>>          cur.execute("""SELECT myco.genus.name
>>              FROM myco.genus
>>              WHERE myco.genus.name LIKE %s""", (genus.upper()+'%',))
>>          lsgenus = cur.fetchall()
>>          ls = []
>>          for genus in lsgenus:
>>              ls.append(genus[0])
>>      return jsonify(ls)
>> --8<--
>>
>> My questions:
>> - What is the best way to use in psycopg3 to express a SELECT ... 
>> WHERE ... LIKE blah% ?
>> - Is my code above safe or vulnerable to a injection attack?
>> - What peoples having passed on the same pattern have to recommend?
> 
> Read:
> 
> https://www.psycopg.org/psycopg3/docs/basic/params.html
> 
> It will answer the above.
> 
> For this case from link:
> 
> "When parameters are used, in order to include a literal % in the query 
> you can use the %% string:"

Actually ignore the above, that only applies if you are using % in the 
query itself not in the supplied arguments.

> 
>>
>> Thanks!
>>
> 

-- 
Adrian Klaver
adrian.klaver@aklaver.com