boost property tree not able retrive records after parsing json

Question

I have a sample json record that I have parsed via boost json parser and saved it to boost property tree to get all key value pairs.ia following code I am able to get first attribute of tree but how can I get second attributes value ? when I try to get it ,it shows me exception that "No such node".

if I iterate the tree ,then it is showing me all keys.I don't understand whats wrong with it. ref : http://www.boost.org/doc/libs/1_52_0/doc/html/boost_propertytree/accessing.html

json string := {"type":"net.aggregate","post.source":"1209010340", "val":1000}

Code:

boost::property_tree::ptree pt;    
read_json("jSon string object", pt);
cout << pt.get("type", ""); // working
cout <<  pt.get("post.source", "") // showing error ....`

try sending slightly different json and see if it works: ...,"post":{"source":"1209010340"},... — bobah, Nov 29 '12 at 11:40
@Lain, please do not label your (several) edits as *Fixed gramatical errors* when what you *really* did was capitalise a few letters. — Sheridan, Mar 01 '14 at 00:53
@Sheridan How should I label it? I find the letters being lower case very annoying to read. — Lain, Mar 01 '14 at 00:53
How about *Capitalised letters* like most people put?... they're hardly *gramatical errors*. — Sheridan, Mar 01 '14 at 00:54
Of course, it doesn't have to be exactly that... I'm just requesting that you label your edits more accurately. And thanks. — Sheridan, Mar 01 '14 at 00:56

score 7 · Answer 1 · answered Mar 29 '13 at 15:30

7

Since the property name contains a dot, you have to use a different separator, so in your case that would be:

cout << pt.get(ptree::path_type("post.source", '/'), "");

Boost documentation section that explains it.

answered Mar 29 '13 at 15:30

Pedja

186
1
8

score 1 · Accepted Answer · answered Nov 29 '12 at 11:40

1

Because Boost property_tree uses the dot to separate different objects. When you request "post.source" the get function looks for an object post with a property source.

answered Nov 29 '12 at 11:40

Some programmer dude

400,186
35
402
621

thanks Joachim Pileborg, please suggest me how can i retrive its value ? – Dhimant Jayswal Nov 29 '12 at 11:48
@DhimantJayswal Either rename it without a dot, or modify the JSON to include the "post" object: `... "post": { "source": ... } ..` – Some programmer dude Nov 29 '12 at 11:52
Json format is fixed for me ,so i cant change the formate of json record. – Dhimant Jayswal Nov 29 '12 at 11:53
@DhimantJayswal Then you have two options: One is that you talk to the supplier of the JSON data you receive, and tell them that they need to change the name of the structure. The second is that you look for another JSON-parser that can handle names with embedded dots. – Some programmer dude Nov 29 '12 at 11:57
Such a useless answer, and also accepted. The other answer suggest how to get the value – BЈовић May 12 '17 at 09:00

boost property tree not able retrive records after parsing json

2 Answers2