:res[content-length] only shows size less than 1 KB

[bryantamayo1]

If one reponse has a size of body less than 1KB it's showed in console. On the contrary, it doesn't, only show a hyphen. I would know the size independently of amount.

[dougwilson]

Hi @bryantamayo1 very sorry for your issue. Unfortunately your issue would likely be outside of morgan, as all the :res[content-length] token does is show the value of res.headers['content-length'], which it would appear is blank in some cases for you. You would likely need to address the cause of that in order to get morgan to display the size.

If you are sure the issue is actually in morgan, certainly we can help here, but would need more information, specifically exact code, details, and instructions on how to replicate your issue so we can troubleshoot it.

[bryantamayo1]

This is my simple code:

import express from 'express';
import morgan from 'morgan';
const compression = require('compression');
const app = express();
const PORT = 3000;

app.use(compression());
app.use(morgan(':remote-addr - :remote-user [:date[clf]] ":method :url HTTP/:http-version" :status :res[content-length] B :total-time ms ":referrer" ":user-agent"'));

app.use("/test", (req, res, next) => {
    const info = [
        {
            "_id": "637289c055a3b946fc1f3cac",
            "title": "tes-100",
            "createdAt": "2022-11-14T18:32:32.134Z"
        },
        {
            "_id": "637289c055a3b946fc1f3cac",
            "title": "tes-100",
            "createdAt": "2022-11-14T18:32:32.134Z"
        },
        {
            "_id": "637289c055a3b946fc1f3cac",
            "title": "tes-100",
            "createdAt": "2022-11-14T18:32:32.134Z"
        },
        {
            "_id": "63728bf15e87a2696b829109",
            "title": "tes-101",
            "createdAt": "2022-11-14T18:41:53.435Z"
        },
        {
            "_id": "63728c2129071c9eaa6498bd",
            "title": "tes-102",
            "createdAt": "2022-11-14T18:42:41.900Z"
        },
        {
            "_id": "637cf65933d5bb594fa14345",
            "title": "tes_6¿?'*^```+`][[[{|@#@~44",
            "description": "tes",
            "createdAt": "2022-11-22T16:18:33.780Z"
        },
        {
            "_id": "637d066ba5b00fdd965d8975",
            "title": "12212",
            "createdAt": "2022-11-22T17:27:07.224Z"
        },
        {
            "_id": "637ffd689df662c79d5b26e7",
            "title": "jueves-1",
            "createdAt": "2022-11-24T23:25:28.518Z"
        },
        {
            "_id": "637ffdd524f8b978c9ebdb7c",
            "title": "jueves-2",
            "createdAt": "2022-11-24T23:27:17.097Z"
        },
        {
            "_id": "637ffe8824f8b978c9ebdba5",
            "title": "jueves-3",
            "createdAt": "2022-11-24T23:30:16.222Z"
        },
        {
            "_id": "637fffaa4992428576a95fdf",
            "title": "jueves-4",
            "description": "descripción - 4",
            "createdAt": "2022-11-24T23:35:06.006Z"
        },
        {
            "_id": "638000979f91bc92350591d9",
            "title": "jueves-5",
            "description": "jueves-5-descripcion-jueves-5-descripcion-jueves-5-descripcion-jueves-5-descripcion-jueves-5-descripcion-jueves-5-descripcion-jueves-5-descripcion-jueves-5-descripcion-jueves-5-descripcion-jueves-5-descripcion-jueves-5-descripcion-jueves-5-descripcion-jueves-5-descripcion-jueves-5-descripcion-jueves-5-descripcion-",
            "createdAt": "2022-11-24T23:39:03.934Z"
        },
        {
            "_id": "63800397fce2f6e6ef63c977",
            "title": "jueves-6",
            "description": "1111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111",
            "createdAt": "2022-11-24T23:51:51.761Z"
        },
        {
            "_id": "6380056739926dbf3682a727",
            "title": "jueves-7",
            "description": "555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555555",
            "createdAt": "2022-11-24T23:59:35.021Z"
        },
        {
            "_id": "63800c0a2e5606728095a98e",
            "title": "b-project-1",
            "createdAt": "2022-11-25T00:27:54.810Z"
        },
        {
            "_id": "63810f8599dfd3c83c560d63",
            "title": "b-project-2",
            "createdAt": "2022-11-25T18:55:01.492Z"
        },
        {
            "_id": "6381207b78e673ce3e8e90da",
            "title": "b-project-3",
            "createdAt": "2022-11-25T20:07:23.193Z"
        },
        {
            "_id": "6384c37b51766f61bbfd9958",
            "title": "project-28-11-2022",
            "createdAt": "2022-11-28T14:19:39.554Z"
        },
        {
            "_id": "63ab2f3bb0fa5258eebf9803",
            "title": "project-27-12-2022",
            "createdAt": "2022-12-27T17:45:31.845Z"
        },
        {
            "_id": "63ab35d1dc3a80576d828b82",
            "title": "project-27-12-2022-v2",
            "createdAt": "2022-12-27T18:13:37.376Z"
        },
        {
            "_id": "63ab3fbd3747463d20479f72",
            "title": "project-27-12-2022-v3",
            "createdAt": "2022-12-27T18:55:57.905Z"
        }
    ];
    return res.json({
        status: "success",
        data: info
    });
});

app.listen(PORT, () => {
    console.log(`[server] is listening on ${PORT}`);
});

And these are my logs:

::1 - - [29/Dec/2022:13:46:29 +0000] "GET /test HTTP/1.1" 200 - B 10.345 ms "-" "PostmanRuntime/7.29.2"

Where is the amount of Bytes?

But if I comment the middleware:

// app.use(compression());

This works and show the amount of Bytes Ok:

::1 - - [29/Dec/2022:13:47:57 +0000] "GET /test HTTP/1.1" 200 3177 B 5.582 ms "-" "PostmanRuntime/7.29.2"

Perhaps is the mistake library compression?

[dyk1454683243-sudo]

I reproduced the example from this thread (Express + compression() + :res[content-length]) on current master.

This is expected morgan behavior, not a ~1KB bug in the token.

:res[content-length] only prints the Content-Length response header. If that header is absent, the documented fallback is - (:res[header] in the README).

The ~1KB cutoff comes from compression's default threshold of 1kb:

• Body under the threshold: not gzipped. Express/Node can set Content-Length, so morgan prints the size.
• Body over the threshold and the client accepts gzip: compression streams the body. HTTP then uses Transfer-Encoding: chunked and omits Content-Length (the compressed length is not known when headers are sent). Morgan correctly logs -.

Setup	Content-Length	Transfer-Encoding	morgan :res[content-length]
~111 B + compression()	111	(none)	111
~3011 B + compression() + Accept-Encoding: gzip	(none)	chunked	-
~3011 B, no compression()	3011	(none)	3011
~3011 B + compression(), no Accept-Encoding	3011	(none)	3011

That matches the follow-up here: commenting out app.use(compression()) makes the byte count appear.

There is nothing for morgan to change on this token. Buffering the body so :res[content-length] always prints a number would break Apache combined/common semantics (this field is the header, not a measured payload size — and with gzip it would not even be the on-the-wire size).

If you need a size for chunked/gzipped responses, that would be a new token (see #102 / #241), not a change to :res[content-length]. For the existing token, set Content-Length yourself, skip compression on that route, or adjust compression({ threshold }).