Details
Minor - P4
Description
The shell trims whitespace when displaying find results, but the data is correctly inserted and can be queried appropriately:
From here: http://dba.stackexchange.com/questions/27200/preserving-whitespace-in-mongodb-values
Quick test to show it happening:
// insert a string with some leading and trailing spaces
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mongos> db.test.insert({"name":" adam "}) |
// now do a find for that string (success)
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mongos> db.test.find({"name":" adam "}) |
{ "_id" : ObjectId("50814e5c2a17d922cd25974f"), "name" : " adam " } |
// however, the display is off - only one leading/trailing space shown
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// just to be sure, search for the output again (no results)
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mongos> db.test.find({"name":" adam "}) |
mongos>
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Issue Links
- is duplicated by
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SERVER-6893
Shell tojson() shouldn't compact multiple adjacent spaces to one.
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- Closed
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Activity
The code is trying to make things print "nicely" when formatting has not been explicitly set and when the output can fit on one line (before processing, hmmm ...). It compresses every block of whitespace to a single space. This is probably helpful for whitespace between fields, but it isn't selective and it smushes whitespace in string fields to a single space.
src/mongo/shell/types.js lines 539 to 545 (in tojson()):
case "object":{
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var s = tojsonObject(x, indent, nolint);
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if ((nolint == null || nolint == true) && s.length < 80 && (indent == null || indent.length == 0)){
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s = s.replace(/[\s\r\n ]+/gm, " ");
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}
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return s;
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}
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If you add text to the object to push its unprocessed length to 80 or more characters, it goes multi-line and you see the spaces:
> adam
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{ "_id" : ObjectId("513dbef8d33345132fe2a81b"), "adam" : " adam " }
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> adam.moreText = "Just add some text"
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Just add some text
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> adam
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{
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"_id" : ObjectId("513dbef8d33345132fe2a81b"),
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"adam" : " adam ",
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"moreText" : "Just add some text"
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}
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You don't need to store and fetch a document to reproduce this, you can just create a local object in the shell.
The regular expression is doing too much. The tojsonObject() function inserts tabs and newlines and doesn't add multiple spaces or carriage returns, so stripping just tabs and newlines gives the more concise display without hammering spaces in strings. Tabs and newlines in strings should already have been escaped to backslash-t and backslash-n, so stripping them should not hurt anything.
> var adam = { "_id" : ObjectId("50816b7e4af6ff7c8679c7d2"), "adam" : " adam " }
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> adam
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{ "_id" : ObjectId("50816b7e4af6ff7c8679c7d2"), "adam" : " adam " }
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> var s = tojsonObject(adam)
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> s
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{
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"_id" : ObjectId("50816b7e4af6ff7c8679c7d2"),
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"adam" : " adam "
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}
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> s.length
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79
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> var u = s.replace(/[\s\r\n ]+/gm, " ");
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> u
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{ "_id" : ObjectId("50816b7e4af6ff7c8679c7d2"), "adam" : " adam " }
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> var v = s.replace(/[\t\n]+/gm, " ");
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> v
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{ "_id" : ObjectId("50816b7e4af6ff7c8679c7d2"), "adam" : " adam " }
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>
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Author:
{u'date': u'2013-03-11T12:35:26Z', u'name': u'Tad Marshall', u'email': u'tad@10gen.com'}Message: SERVER-7424 Use simpler regex to produce single line output in tojson()
When displaying small objects, convert only tabs, carriage returns and
newlines to single spaces, leaving other whitespace alone.
Branch: master
https://github.com/mongodb/mongo/commit/d36db8ac30a56d39f4af58e573ee417450798c96
Author:
{u'date': u'2013-03-11T12:35:26Z', u'name': u'Tad Marshall', u'email': u'tad@10gen.com'}Message: SERVER-7424 Use simpler regex to produce single line output in tojson()
When displaying small objects, convert only tabs, carriage returns and
newlines to single spaces, leaving other whitespace alone.
Branch: v2.4
https://github.com/mongodb/mongo/commit/63f4bc287d175ab3414025402c47b00c2f238ac9
Yes, something funny in the display code:
> db.b.insert({adam:" adam "})> var adam=db.b.find({adam:{$exists:1}}).next()> adam{ "_id" : ObjectId("50816b7e4af6ff7c8679c7d2"), "adam" : " adam " }> printjson(adam){ "_id" : ObjectId("50816b7e4af6ff7c8679c7d2"), "adam" : " adam " }> printjsononeline(adam){ "_id" : ObjectId("50816b7e4af6ff7c8679c7d2"), "adam" : " adam " }