We're always looking for ways to improve the developer experience and reduce complexity across your application development pipeline. One way you can use Supabase to do that is with dynamic JavaScript in Edge Functions. This greatly increases the versatility of your edge functions and reduces the need for you to redeploy your functions if you need to change business logic.
Edge Functions in Supabase are serverless functions that execute in response to HTTP requests. These functions are deployed at the edge, meaning they run close to the user's location, resulting in faster response times.
Dynamic code execution allows you to modify and run JavaScript code on the fly without having to redeploy your function each time the code changes. This is particularly useful when you need the flexibility to execute different logic depending on the incoming request, without incurring the overhead of redeployment.
We have a repo with the SQL script to create helper functions to support the dynamic execution of JavaScript code. You can find the repo here: supa-dynamic
Install the SQL script supa-dynamic--0.1.sql from the repo in your Supabase project. (You can copy and paste the code from the repo into the SQL editor in your Supabase project.)
These are the functions we'll use to execute the JavaScript code:
You can skip this section if you are only interested in using the dynamic execution of JavaScript code. However, if you want to understand how the helper functions work, keep reading.
This function handles the actual HTTP request and processes the response. It ensures consistency in response format.
_45
CREATE OR REPLACE FUNCTION edge.http_request(
_45
url TEXT,
_45
method TEXT DEFAULT 'POST',
_45
headers JSONB DEFAULT '{"Content-Type": "application/json"}'::jsonb,
_45
params JSONB DEFAULT '{}'::jsonb,
_45
payload JSONB DEFAULT '{}'::jsonb,
_45
timeout_ms INTEGER DEFAULT 5000
_45
) RETURNS jsonb AS $$
_45
DECLARE
_45
http_response extensions.http_response;
_45
status_code integer := 0;
_45
response_json jsonb;
_45
response_text text;
_45
header_array extensions.http_header[];
_45
request extensions.http_request;
_45
BEGIN
_45
-- Set the timeout option
_45
IF timeout_ms > 0 THEN
_45
PERFORM http_set_curlopt('CURLOPT_TIMEOUT_MS', timeout_ms::text);
_45
END IF;
_45
_45
-- Convert headers JSONB to http_header array
_45
SELECT array_agg(extensions.http_header(key, value::text))
_45
FROM jsonb_each_text(headers)
_45
INTO header_array;
_45
_45
-- Construct the http_request composite type
_45
request := ROW(method, url, header_array, 'application/json', payload::text)::extensions.http_request;
_45
_45
-- Make the HTTP request
_45
http_response := http(request);
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status_code := http_response.status;
_45
_45
-- Attempt to extract JSONB response content
_45
BEGIN
_45
response_json := http_response.content::jsonb;
_45
EXCEPTION
_45
WHEN others THEN
_45
response_text := http_response.content;
_45
response_json := jsonb_build_object('status_code', status_code, 'response', response_text);
_45
END;
_45
_45
RETURN jsonb_build_object('status_code', status_code, 'response', response_json);
_45
END;
_45
$$ LANGUAGE plpgsql;
The edge_wrapper function manages HTTP requests with features like retries, custom headers, and region selection. Below are the parameters it accepts:
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CREATE OR REPLACE FUNCTION edge.edge_wrapper(
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url TEXT,
_87
method TEXT DEFAULT 'POST',
_87
headers JSONB DEFAULT '{"Content-Type": "application/json"}'::jsonb,
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params JSONB DEFAULT '{}'::jsonb,
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payload JSONB DEFAULT '{}'::jsonb, -- Payload as JSONB
_87
timeout_ms INTEGER DEFAULT 5000,
_87
max_retries INTEGER DEFAULT 0,
_87
allowed_regions TEXT[] DEFAULT NULL
_87
) RETURNS jsonb AS $$
_87
DECLARE
_87
retry_count INTEGER := 0;
_87
retry_delays DOUBLE PRECISION[] := ARRAY[0, 0.250, 0.500, 1.000, 2.500, 5.000];
_87
succeeded BOOLEAN := FALSE;
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current_region_index INTEGER := 1; -- Start index at 1 for PostgreSQL array
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combined_headers JSONB;
_87
response_json JSONB;
_87
BEGIN
_87
-- Validate headers, params, and payload are JSON objects
_87
IF headers IS NULL OR NOT jsonb_typeof(headers) = 'object' THEN
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RAISE EXCEPTION 'Invalid headers parameter: %', headers;
_87
END IF;
_87
_87
IF params IS NULL OR NOT jsonb_typeof(params) = 'object' THEN
_87
RAISE EXCEPTION 'Invalid params parameter: %', params;
_87
END IF;
_87
_87
IF payload IS NULL OR NOT jsonb_typeof(payload) = 'object' THEN
_87
RAISE EXCEPTION 'Invalid payload parameter: %', payload;
_87
END IF;
_87
_87
-- Validate allowed_regions if provided
_87
IF allowed_regions IS NOT NULL AND cardinality(allowed_regions) = 0 THEN
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RAISE EXCEPTION 'allowed_regions parameter cannot be an empty array';
_87
END IF;
_87
_87
-- Check if retry_delays has enough elements
_87
IF cardinality(retry_delays) < max_retries + 1 THEN
_87
RAISE EXCEPTION 'retry_delays array must have at least % elements', max_retries + 1;
_87
END IF;
_87
_87
-- Retry loop
_87
WHILE NOT succeeded AND retry_count <= max_retries LOOP
_87
combined_headers := headers;
_87
_87
-- Set x-region header if allowed_regions is provided
_87
IF allowed_regions IS NOT NULL AND cardinality(allowed_regions) > 0 THEN
_87
combined_headers := combined_headers || jsonb_build_object('x-region', allowed_regions[current_region_index]);
_87
END IF;
_87
_87
-- Sleep if not the first attempt
_87
IF retry_count > 0 THEN
_87
PERFORM pg_sleep(retry_delays[retry_count]);
_87
END IF;
_87
_87
retry_count := retry_count + 1;
_87
_87
-- Increment region index, wrapping around if necessary
_87
IF allowed_regions IS NOT NULL AND cardinality(allowed_regions) > 0 THEN
_87
current_region_index := current_region_index + 1;
_87
IF current_region_index > cardinality(allowed_regions) THEN
_87
current_region_index := 1;
_87
END IF;
_87
END IF;
_87
_87
BEGIN
_87
RAISE WARNING 'headers:%s', combined_headers;
_87
_87
-- Call the simplified HTTP request function
_87
response_json := edge.http_request(url, method, combined_headers, params, payload, timeout_ms);
_87
_87
-- Check the status code
_87
IF (response_json->>'status_code')::INTEGER < 500 THEN
_87
succeeded := TRUE;
_87
END IF;
_87
EXCEPTION
_87
WHEN OTHERS THEN
_87
IF retry_count > max_retries THEN
_87
RAISE EXCEPTION 'HTTP request failed after % retries. SQL Error: { %, % }',
_87
max_retries, SQLERRM, SQLSTATE;
_87
END IF;
_87
END;
_87
END LOOP;
_87
_87
RETURN response_json;
_87
END;
_87
$$ LANGUAGE plpgsql;
To securely manage secrets, you will need to set your service_role_key in Vault. Here’s how you can create a function to retrieve secrets:
_17
CREATE OR REPLACE FUNCTION edge.get_secret(secret_name text) RETURNS text
_17
LANGUAGE "plpgsql"
_17
AS $$
_17
DECLARE
_17
decrypted text;
_17
BEGIN
_17
IF current_setting('request.jwt.claims', true)::jsonb->>'role' = 'service_role' OR current_user = 'postgres' THEN
_17
SELECT decrypted_secret
_17
INTO decrypted
_17
FROM vault.decrypted_secrets
_17
WHERE name = secret_name;
_17
RETURN decrypted;
_17
ELSE
_17
RAISE EXCEPTION 'Access denied: only service_role or postgres user can execute this function.';
_17
END IF;
_17
END;
_17
$$;
This function can retrieve the service_role secret from Vault, it also ensures that only authorized roles can access sensitive environment variables.
Let's dive into the code and set up our dynamic JavaScript executor Edge Function using Deno. Below is an overview of how to accomplish this.
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supabase functions new multi-purpose
Now, we'll edit the code adding verification and the eval function, including the supabase client so we have it ready without the need to import.
_44
import "jsr:@supabase/functions-js/edge-runtime.d.ts";
_44
_44
// Import the supabase client
_44
import { createClient } from "<https://esm.sh/@supabase/supabase-js@2>";
_44
_44
console.log("===\\n\\tBooted Edge Worker!\\n===\\n");
_44
const supabase_url = Deno.env.get("SUPABASE_URL") ?? "";
_44
const service_role = Deno.env.get("SUPABASE_SERVICE_ROLE_KEY");
_44
// Set the permission to service_role key:
_44
const supabase = createClient(supabase_url, service_role);
_44
// This allows us to use Supabase.ai in the function
_44
const session = new Supabase.ai.Session('gte-small');
_44
_44
Deno.serve(async (req: Request) =>
_44
const authorization = req.headers.get("Authorization");
_44
if (!authorization) throw new Error("Authorization header is missing.");
_44
// Ensures that the function is called with service_role to prevent missuse
_44
if (!authorization.includes(service_role)) {
_44
throw new Error("Authorization header is invalid.");
_44
}
_44
_44
const { code } = await req.json();
_44
try {
_44
// Wrap the provided code in an async function context
_44
const asyncFunction = new Function('supabase', `
_44
return (async () => {
_44
${code.replace(/\\\\/g, '')}
_44
})();
_44
`);
_44
// Pass the Supabase client as the scope for the function to use:
_44
const data = await asyncFunction(supabase);
_44
console.log(data);
_44
return new Response(
_44
JSON.stringify({ data }),
_44
{ headers: { 'Content-Type': 'application/json', 'Connection': 'keep-alive' } },
_44
);
_44
} catch (error) {
_44
console.error("Error executing user code:", error);
_44
return new Response(
_44
JSON.stringify({ error: "An error occurred -> " + error.message }),
_44
{ status: 500, headers: { "Content-Type": "application/json" } }
_44
);
_44
}
_44
});
_10
const authorization = req.headers.get('Authorization')
_10
if (!authorization) throw new Error('Authorization header is missing.')
_10
// Ensures that the function is called with service_role to prevent missuse
_10
if (!authorization.includes(service_role)) {
_10
throw new Error('Authorization header is invalid.')
_10
}
_10
const { code } = await req.json()
_10
try {
_10
// Wrap the provided code in an async function context
_10
const asyncFunction = new Function('supabase', `
_10
return (async () => {
_10
${code.replace(/\\\\/g, '')}
_10
})();
_10
`);
_10
}
_10
// Pass the Supabase client as the scope for the function to use:
_10
const data = await asyncFunction(supabase)
_10
console.log(data)
_10
return new Response(JSON.stringify({ data }), {
_10
headers: { 'Content-Type': 'application/json', Connection: 'keep-alive' },
_10
})
To deploy this Edge Function, you'll need to use the Supabase CLI. Ensure you have Docker installed and running on your local machine. Follow these steps to deploy:
We are using the helper functions defined earlier to create a function that interacts with the edge function. This function will execute the dynamic JavaScript code and return the results. This is the main function that will be used to execute the dynamic JavaScript code and return the results.
The edge.exec is a simple function leverages edge_wrapper to execute dynamic JavaScript code. Here's an example of how it is structured:
_23
CREATE OR REPLACE FUNCTION edge.exec(data text) RETURNS JSONB LANGUAGE plpgsql
_23
AS $function$
_23
DECLARE
_23
custom_headers JSONB;
_23
-- Example restricting regions available to Europe
_23
allowed_regions TEXT[] := ARRAY['eu-west-1', 'eu-west-2', 'eu-west-3', 'eu-north-1', 'eu-central-1'];
_23
BEGIN
_23
-- Set headers with anon key and Content-Type
_23
custom_headers := jsonb_build_object(
_23
'Authorization', 'Bearer ' || edge.get_secret('service_role_key'),
_23
'Content-Type', 'application/json',
_23
'x-region', allowed_regions
_23
);
_23
-- Call edge_wrapper function with default values
_23
RETURN edge.edge_wrapper(
_23
url := ('https://<ref>.supabase.co/functions/v1/multi-purpose'),
_23
headers := custom_headers,
_23
payload := jsonb_build_object('code', data),
_23
max_retries := 5,
_23
allowed_regions := allowed_regions
_23
);
_23
END;
_23
$function$;
The key to executing the dynamic JavaScript code is wrapping it in an async function context using new Function(). This approach lets you evaluate the code in isolation while retaining access to the supabase client for interacting with your database. You can check the examples of how to use this calling the supabase client or even generating embeddings.
To demonstrate the execution of dynamic JavaScript, you can use the Supabase client libraries within the SQL context. Here’s an example query:
_12
SELECT edge.exec(
_12
$js$
_12
const { data, error } = await supabase.rpc('postgres_function', {'foo': 'bar'});
_12
if (error) {
_12
return new Response(JSON.stringify({ error: "An error occurred ->" + error.message }), {
_12
status: 500,
_12
headers: { "Content-Type": "application/json" },
_12
});
_12
}
_12
return data;
_12
$js$
_12
);
The edge.exec function allows for dynamic JavaScript execution, such as interacting with an AI session to generate embeddings. When executed, the JavaScript code within the SQL context runs through the edge function, returning results to the database.
_10
select edge.exec(
_10
$js$
_10
_10
const session = new Supabase.ai.Session('gte-small');
_10
return await session.run('hello world');
_10
_10
$js$);
_22
CREATE OR REPLACE FUNCTION edge.generate_embedding(input_text TEXT) RETURNS JSONB AS $$
_22
DECLARE
_22
response JSONB;
_22
BEGIN
_22
-- Call the edge function to generate the embedding for the provided text
_22
response := edge.exec(
_22
format(
_22
$js$
_22
const session = new Supabase.ai.Session('gte-small');
_22
return await session.run(%L);
_22
$js$,
_22
input_text
_22
)
_22
);
_22
RETURN response->'response'->'data';
_22
END;
_22
$$ LANGUAGE plpgsql;
_22
_22
select edge.generate_embedding('The quick brown fox jumps over the lazy dog');
_22
_22
-- response:
_22
-- [-0.07254139333963394,-0.02173878252506256,0.042930446565151215,0.04853367060422897,0.015609614551067352,0.02912059798836708,0.0371023565530777,0.05054798722267151,0.0035842431243509054,0.0015563230263069272,0.0009484672918915749,-0.09247169643640518,0.04190639406442642,0.05874202027916908,-0.012341015040874481,0.01661474071443081,-0.013452880084514618,0.003742767730727792,-0.07664268463850021,0.03231268376111984,0.0006968052475713193,-0.06508929282426834,-0.04956015944480896,-0.014327225275337696,0.03270547464489937,0.01635774038732052,-0.022707758471369743,-0.007586371619254351,-0.03548099845647812,-0.17844657599925995,0.03325255215167999,-0.07009242475032806,0.02982083335518837,-0.05649203434586525,-0.006693259347230196,-0.02781110256910324,-0.01687553897500038,0.04976152256131172,-0.015715090557932854,0.038247860968112946,0.040495794266462326,-0.007263457402586937,-0.019288228824734688,-0.0527581050992012,-0.0065462407656013966,-0.022786622866988182,-0.04975651577115059,-0.04053974151611328,0.03047902137041092,-0.05064946785569191,-0.023929744958877563,-0.03891737014055252,0.03785012289881706,-0.0133274607360363,0.03001898154616356,-0.007281183265149593,0.060004156082868576,0.017414024099707603,0.025516854599118233,0.029599720612168312,0.02893918938934803,0.03455337509512901,-0.14698833227157593,0.09387505799531937,0.05768263339996338,0.019130567088723183,-0.0380706787109375,-0.04105521738529205,0.008963614702224731,0.012743324972689152,0.009223062545061111,0.060711149126291275,0.007398003712296486,0.04229794815182686,0.046996768563985825,-0.003397924592718482,0.00808036606758833,0.022617157548666,-0.01847437582910061,0.0026343590579926968,-0.010598739609122276,-0.037673674523830414,-0.04375630244612694,-0.0007789010996930301,-0.007935777306556702,-0.03272915259003639,0.021433845162391663,-0.07967976480722427,0.06888656318187714,0.07489841431379318,-0.02783842757344246,-0.006374717690050602,-0.035476282238960266,0.006344574969261885,-0.03357071802020073,-0.036727335304021835,0.012309364043176174,-0.00006389369809767231,-0.053050097078084946,0.19709722697734833,-0.05575009435415268,0.05757850036025047,0.0951322615146637,-0.04633559286594391,0.03476420044898987,0.012983368709683418,0.0004390157700981945,0.010212302207946777,-0.012741461396217346,0.014706282876431942,0.03321540355682373,-0.006495281588286161,0.041682176291942596,0.003406582633033395,0.02581774815917015,-0.0007246752502396703,0.011133069172501564,0.08353550732135773,0.006477882619947195,0.00224463758058846,0.020395604893565178,-0.013416256755590439,0.05663946643471718,-0.028388522565364838,0.019082417711615562,-0.08387858420610428,0.054498571902513504,0.10694538056850433,0.06286843866109848,0.03180928900837898,0.037740662693977356,-0.07479764521121979,0.010231229476630688,-0.04866624251008034,0.004061027429997921,0.0362103171646595,-0.009540606290102005,0.00915283989161253,0.031154874712228775,-0.04876647889614105,-0.015956921502947807,-0.1429857611656189,-0.01470054779201746,-0.09399641305208206,-0.019157350063323975,0.02896934375166893,-0.018669532611966133,0.014991801232099533,-0.06764508783817291,0.027312103658914566,-0.003859955817461014,0.025718173012137413,-0.018675100058317184,-0.016409857198596,-0.021459592506289482,0.004702075384557247,-0.0323822982609272,0.10394860059022903,-0.020106177777051926,-0.008876764215528965,-0.027185838669538498,0.0003392586368136108,-0.009877108968794346,-0.0004303457390051335,0.04185814782977104,-0.05188998952507973,-0.021185973659157753,0.00026368125691078603,-0.02180171199142933,-0.03400561958551407,0.020068379119038582,0.034275852143764496,-0.10943055897951126,0.031987469643354416,0.054017845541238785,-0.009243185631930828,-0.07103140652179718,0.00785127654671669,-0.0040434580296278,-0.05036382004618645,0.07858535647392273,-0.08356015384197235,-0.06914680451154709,0.06180981919169426,0.043073058128356934,-0.020246226340532303,-0.015496478416025639,-0.005946696270257235,0.006562687456607819,0.04845070466399193,-0.029123008251190186,0.02194702997803688,0.002446065191179514,-0.06825454533100128,-0.07056894898414612,0.01598423719406128,-0.04185032472014427,-0.01633128523826599,0.014294272288680077,-0.01768324337899685,0.05590462312102318,-0.044063832610845566,0.02461099997162819,0.0006756667862646282,0.07429251074790955,0.011551265604794025,0.014212443493306637,-0.02237367257475853,0.039057254791259766,0.000325449975207448,-0.004185846075415611,-0.003040974261239171,0.01800958439707756,-0.02479490265250206,-0.019247515127062798,0.04366869106888771,-0.027130864560604095,0.018955133855342865,0.03239727392792702,0.03226468712091446,0.06487660109996796,-0.06456360220909119,0.0006639647181145847,-0.20788206160068512,0.05066373199224472,-0.012870946899056435,-0.034873317927122116,0.023824242874979973,-0.02305314689874649,0.030056791380047798,-0.06937119364738464,0.0642433762550354,0.05418730527162552,0.06050065532326698,-0.04655877873301506,-0.026898164302110672,-0.003803820814937353,0.002598312683403492,0.1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_10
select edge.exec(
_10
$js$
_10
_10
const { data, error } = await supabase.auth.admin.createUser({
_10
email: 'user@email.com',
_10
password: 'password',
_10
user_metadata: { name: 'Yoda' }
_10
});
_10
_10
$js$));
As you can see, combining dynamic Javascript in Edge Functions with a few SQL support functions gets you a powerful new set of tools. By leveraging the edge_wrapper, edge.http_request, and edge.exec functions, developers can create robust and flexible serverless applications that can dynamically execute JavaScript code while interacting with PostgreSQL databases.
As we continue to build and innovate with Supabase, combining edge functions and SQL support functions opens up new avenues for building scalable, efficient, and secure applications. Whether developing a simple project or a complex application, these tools provide the flexibility and power to bring your ideas to life.
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