erlang convert complex binary structure to JSON - erlang

I have a binary <<"{\"resp_child\":\"0\"}\n">> (as you can see it includes JSON) and I would like to extract this 0 as binary <<0>> from this binary.
I am new to erlang, i was trying
string:join(binary_to_list(<<"{\"resp_child\":\"0\"}\n">>), "")
but i get the JSON string as a result.
"{\"resp_child\":\"0\"}\n"
Don't know what to do further to get <<0>>.
Thank you.

Why not to use one of the Erlang JSON parsing library?
jsx
jiffy
mochijson2
proplists:get_value(<<"resp_child">>, jsx:decode(<<"{\"resp_child\":\"0\"}\n">>)).
So if you need to replace <<"0">>, <<"1">>, ... <<"9">> to <<0>>, <<1>>, ... <<9>> you can write converting function for this

Yeah, this code worked for me.
Struct = mochijson2:decode(<<"{\"resp_child\":\"0\"}\n">>),
{struct, JsonData} = Struct,
Digits = proplists:get_value(<<"resp_child">>, JsonData).
Digits is <<0>>, that what i want.
You can read more about proplists at: http://www.erlang.org/doc/man/proplists.html.
Thanks :)

Related

How do I convert esp.flash_read() to string

I have the following code:
buff=esp.flash_read(esp.flash_user_start(),50)
print(buff)
I get the following output from print:
bytearray(b'{"ssid": "mySSID", "password": "myPASSWD"}\xff\xff\xff\xff\xff\xff')
What I want to do is get the json in buff. What is the correct "Python-way" to do that?
buff is a Python bytes object, as shown by the print output beginning with b'. To convert this into a string you need to decode it.
In standard Python you could use
buff.decode(errors='ignore')
Note that without specifying errors=ignore you would get a UnicodeDecodeError because the \xff bytes aren't valid in the default encoding, which is UTF-8; presumably they're padding and you want to ignore them.
If that works on the ESP8266, great! However this from the MicroPython docs suggests the keyword syntax might not be implemented - I don't have an ESP8266 to test it. If not then you may need to remove the padding characters yourself:
textLength = find(buff, b'\xff')
text = buff[0:textLength].decode()
or simply:
text = buff[0:buff.find(b'\xff')].decode()
If decode isn't implemented either, which it isn't in the online MicroPython interpreter, you can use str:
text = str(buff[0:find(buff, b'\xff')], 'utf-8')
Here you have to specify explicitly that you're decoding from UTF-8 (or whatever encoding you specify).
However if what you're really after is the values encoded in the JSON, you should be able to use the json module to retrieve them into a dict:
import json
j = json.loads(buff[0:buff.find(b'\xff')])
ssid = j['ssid']
password = j['password']

Array.size() returned wrong values (Grails)

I'm developing an app using Grails. I want to get length of array.
I got a wrong value. Here is my code,
def Medias = params.medias
println params.medias // I got [37, 40]
println params.medias.size() // I got 7 but it should be 2
What I did wrong ?
Thanks for help.
What is params.medias (where is it being set)?
If Grials is treating it as a string, then using size() will return the length of the string, rather than an array.
Does:
println params.medias.length
also return 7?
You can check what Grails thinks an object is by using the assert keyword.
If it is indeed a string, you can try the following code to convert it into an array:
def mediasArray = Eval.me(params.medias)
println mediasArray.size()
The downside of this is that Eval presents the possibility of unwanted code execution if the params.medias is provided by an end user, or can be maliciously modified outside of your compiled code.
A good snippet on the "evil (or lack thereof) of eval" is here if you're interested (not mine):
https://javascriptweblog.wordpress.com/2010/04/19/how-evil-is-eval/
I think 7 is result of length of the string : "[37,40]"
Seems your media variable is an array not a collection
Try : params.medias.length
Thanks to everyone. I've found my mistake
First of all, I sent an array from client and my params.medias returned null,so I converted it to string but it is a wrong way.
Finally, I sent and array from client as array and in the grails, I got a params by
params."medias[]"
List medias = params.list('medias')
Documentation: http://grails.github.io/grails-doc/latest/guide/single.html#typeConverters

rails decode json cyrrilic string

I have such string example, which i get from json (cp1251):
Ôèëüòð ìàñëÿíûé OPEL/GM/DAEWOO
which mean:
Фильтр масляный OPEL/GM/DAEWOO
this tool http://www.artlebedev.ru/tools/decoder/ say that i must use CP1252 → CP1251 decoder. I try it so:
my_string.force_encoding('cp1252').force_encoding('1251')
but it didn't solve my problem. What i do wrong?
how could i convert to normall view my json cyrrillic string in RoR?
i get json from url so:
jsonAE = JSON.load(open('http://******/portal.api?l=*****&p=Sih2*****&act=price_by_nr_firm&nr='+article_nr+'&oe=true'))
from json i get:
{"result":[{"nr":"OC90","brand":"Knecht","name":"Фильтр масляный OPEL/GM/DAEWOO","stock":"-","delivery":"не известно","minq":"1","upd":"16.03.15 23:40","price":"130.34","currency":"руб."},{"nr":"OC90","brand":"Knecht","name":‌​"Фильтр масляный OPEL/GM/DAEWOO","stock":"-","delivery":"не известно","minq":"1","upd":"17.03.15 00:05","price":"130.34","currency":"руб."}]}
but it turn's to something bad with JSON.load
▶ puts 'Ôèëüòð ìàñëÿíûé OPEL/GM/DAEWOO'
.encode(Encoding::CP1252)
.force_encoding(Encoding::CP1251)
.encode(Encoding::UTF_8)
#⇒ Фильтр масляный OPEL/GM/DAEWOO
The string in ruby is suspected to be utf8ed. So, the first action is to inform ruby that the string is actually in one-byte. Than we say “hey, don’t care, I know this one-byte is actually cyrillic.” And, finally, turn it back to utf-8.
Hope it helps.

string manipulation in ruby on rails

I have a string of the format,
/d.phpsoft_id=369242&url=http://f.1mobile.com/mobile_software/finance/com.mshift.android.achieva_2.apk
and i need to edit this string using regular expression that the result string should start from http: ie the resultatnt string should be
http://f.1mobile.com/mobile_software/finance/com.mshift.android.achieva_2.apk
please help
For these types of situations, I prefer to go with readily available tools that will help provide a solution or at the very least will point me in the right direction. My favourite for regex is txt2re because it will output example code in many languages, including ruby.
After running your string through the parser and selecting httpurl for matching, it output:
txt='/d.phpsoft_id=369242&url=http://f.1mobile.com/mobile_software/finance/com.mshift.android.achieva_2.apk'
re1='.*?' # Non-greedy match on filler
re2='((?:http|https)(?::\\/{2}[\\w]+)(?:[\\/|\\.]?)(?:[^\\s"]*))' # HTTP URL 1
re=(re1+re2)
m=Regexp.new(re,Regexp::IGNORECASE);
if m.match(txt)
httpurl1=m.match(txt)[1];
puts "("<<httpurl1<<")"<< "\n"
end
str = "/d.phpsoft_id=369242&url=http://f.1mobile.com/mobile_software/finance/com.mshift.android.achieva_2.apk"
str.spl­it("url=")­[1]
Simple Answer
You need to do following
str = "/d.phpsoft_id=369242&url=http://f.1mobile.com/mobile_software/finance/com.mshift.android.achieva_2.apk"
start=str.index('http://')
resultant=str[start,str.length]

NSString to NSDictionary

I have a string (from HTTP Header) and want to split it into a dictionary.
foo = \"bar\",baz=\"fooz\", beta= \"gamma\"
I ca not guarantee that the string is the same every time. Maybe there are spaces, maybe not, sometimes the double quotes are escaped, sometimes not.
So I found the solution in PHP with regular expressions. Unfortunately I can't convert it to work on iOS.
preg_match_all('#('.$key.')=(?:([\'"])([^\2]+?)\2|([^\s,]+))#', $input, $hits, PREG_SET_ORDER);
foreach ($hits as $hit) {
$data[hit[1]] = $hit[3] ? $hit[3] : $hit[4];
}
Can anybody help me converting this to Objective-C?
I met a guy which is kinda RegEx guru. He explained the whole stuff and I got the following (working!!!!) solution in RegEx.
This gives me strings like foo="bar":
(?<=[,\\s])((realm|qop|nonce|opaque)=(?:([\"'])([^\2]+?)\2|([^\\s,]+)))
I then use another RegEx to split it by key and value to create a dictionary.

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