MongocampAggregationBuilder

Build and run an aggregation pipeline on a collection without leaving the UI: group and count, compute fields, sort and limit — then page through the result and export it. Two views of the same pipeline: a Stages editor and a plain JSON view.

Usage

<template>
  <MongocampAggregationBuilder collection-name="myCollection" />
</template>

The playground has it at /secured/admin/collections/<name>/aggregate, linked from the collection's data and info pages.

Props

Prop	Type	Description
collectionName	string	Required. Collection the pipeline runs on. Changing it clears the shown result.

The two views

Stages — a list of stages, each the JSON text of its value. Add a stage by type ($match, $group, $sort, $project, $limit), move it up or down, or remove it. A new stage starts with a sensible example ($group → { "_id": "$field", "count": { "$sum": 1 } }). The text is kept as typed, so a half-written value is never lost.

Stage	Value	Notes
$match	an object	filter documents (MongoDB query syntax, not Lucene)
$group	an object with _id	{ "_id": "$field", "n": { "$sum": 1 } }; "_id": null groups everything
$sort	an object of 1 / -1	{ "n": -1 }
$project	an object	pick or compute fields
$limit	a whole number ≥ 1	a typed "10" is sent as the number 10

A stage with nothing in it ({} or empty) is left out of the request.

JSON — the pipeline as the usual array, [ { "$match": { … } }, { "$limit": 10 } ]. Any stage the server understands can be typed here, including ones the stage editor has no form for ($unwind, $sample, $addFields, $facet, $count, …).

Switching is guarded in both directions: a stage with a mistake blocks leaving the stage editor, and a pipeline using a stage the editor has no form for keeps you in the JSON view. Both say why.

Mistakes are caught before the server sees them

Live, under the stage or the JSON: not valid JSON; a stage value that is not an object; a $limit that is not a whole number of 1 or more; a $sort direction other than 1/-1; a $group without _id; in the JSON view also "not an array", "more than 50 stages", and a stage that is not an object with exactly one $-named key (the message names the stage number). Run stays disabled while there is any mistake.

What is not allowed, and why

These operators are refused anywhere in a pipeline — as a stage or nested inside another stage's value (a $function hides inside $addFields, a $lookup inside a $facet):

Operator	Why
$function, $accumulator, $where	run JavaScript on the database server
$out, $merge	write to collections
$lookup, $unionWith, $graphLookup	read other collections

The refusal names the operator (and the stage in the JSON view). It exists because the MongoCamp server this was verified against (1.5.10) does not restrict aggregation stages: a $function stage executed JavaScript, and $lookup/$unionWith read other collections (whether the user's per-collection grants apply to them was not tested). The same check runs again in useMongocampAggregation().runAggregation, so nothing that bypasses this component can send such a pipeline either. Only keys count: a string value or field name such as "$out" or merge is just data. (On that server $out and $merge cannot run anyway: it answers that they must be the final stage, and its own paging stages always follow.)

Running and results

Run sends the pipeline and shows the first page.

• Paging is done by the server: the page-size select (10 / 20 / 50 / 100, default 20) and the pager re-run the pipeline that produced the result, not whatever has been typed since. Changing the page size goes back to page 1. A run that is overtaken by a newer one is ignored.
• The table has one column per key found in the first rows, _id first (a $group's key). Objects and arrays show as compact JSON with the full text as a tooltip; very long values are shortened.
• The header shows the total number of results. Export (download icon) saves the current page as JSON or CSV — raise the page size first for more.
• A pipeline with no results shows an empty state, not an error.
• Results are plain JSON: dates arrive as ISO text (without milliseconds) and whole numbers beyond 2^53 may already be rounded — a note under the table says so.

When it fails

A failed run shows an alert with the reason and Retry (or Log in again when the session has expired). For a command MongoDB rejects, only MongoDB's own message is shown — the server's raw error also contains the address of the database server, which is never displayed. A request blocked on its way to the server (an intermittent 405 was seen) is reported as retryable.

Not included

Saving or sharing pipelines, charts, field-name autocomplete, and stages beyond the five forms (use the JSON view). Pipelines are read-only by design — nothing here writes data.

Related

• useMongocampAggregation — the calls behind it
• Strings live under nuxtUiMongocamp.aggregation.* in the English and German locale files