I have a lua script, which simplified is like this:
local item = {};
local id = redis.call("INCR", "counter");
item["id"] = id;
item["data"] = KEYS[1]
redis.call("SET", "item:" .. id, cjson.encode(item));
return cjson.encode(item);
KEYS[1] is a stringified json object:
JSON.stringify({name : 'some name'});
What happens is that because I'm using cjson.encode to add the item to the set, it seems to be getting stringified twice, so the result is:
{"id":20,"data":"{\"name\":\"some name\"}"}
Is there a better way to be handling this?
First, regardless your question, you're using KEYS the wrong way and your script isn't written according to the guidelines. You should not generate key names in your script (i.e. call SET with "item:" .. id as a keyname) but rather use the KEYS input array to declare any keys involved a priori.
Secondly, instead of passing the stringified string with KEYS, use the ARGV input array.
Thirdly, you can do item["data"] = json.decode(ARGV[1]) to avoid the double encoding.
Lastly, perhaps you should learn about Redis' Hash data type - it may be more suitable to your needs.
Related
i have extracted the fix message as below from Unix server and now need to convert this message into JSON. how can we do this?
8=FIXT.1.1|9=449|11=ABCD1|35=AE|34=1734|49=REPOFIXUAT|52=20140402-11:38:34|56=TR_UAT_VENDOR|1128=8|15=GBP|31=1.7666|32=50000000.00|55=GBP/USD|60=20140402-11:07:33|63=B|64=20140415|65=OR|75=20140402|150=F|167=FOR|194=1.7654|195=0.0012|460=4|571=7852455|1003=2 USD|1056=88330000.00|1057=N|552=1|54=2|37=20140402-12:36:48|11=NOREF|453=4|448=ZERO|447=D|452=3|448=MBY2|447=D|452=1|448=LMEB|447=D|452=16|448=DOR|447=D|452=11|826=0|78=1|79=default|80=50000000.00|5967=88330000.00|10=111
Note: I tried to make this a comment on the answer provided by #selbie, but the text was too long for a comment, so I am making it an answer.
#selbie's answer will work most of the time, but there are two edge cases in which it could fail.
First, in a tag=value field where the value is of type STRING, it is legal for value to contain the = character. To correctly cope with this possibility, the Java statement:
pair = item.split("=");
should be changed to:
pair = item.split("=", 2);
The second edge case is when there are a pair of fields, the first of which is of type LENGTH and the second is of type DATA. In this case, the value of the LENGTH fields specifies the length of the DATA field (without the delimiter), and it is legal for the value of the DATA field to contain the delimiter character (ASCII character 1, but denoted as | in both the question and Selbie's answer). Selbie's code cannot be modified in a trivial manner to deal with this edge case. Instead, you will need a more complex algorithm that consults a FIX data dictionary to determine the type of each field.
Since you didn't tag your question for any particular programming language, I'll give you a few sample solutions:
In javascript:
let s = "8=FIXT.1.1|9=449|11=ABCD1|35=AE|34=1734|49=REPOFIXUAT|52=20140402-11:38:34|56=TR_UAT_VENDOR|1128=8|15=GBP|31=1.7666|32=50000000.00|55=GBP/USD|60=20140402-11:07:33|63=B|64=20140415|65=OR|75=20140402|150=F|167=FOR|194=1.7654|195=0.0012|460=4|571=7852455|1003=2 USD|1056=88330000.00|1057=N|552=1|54=2|37=20140402-12:36:48|11=NOREF|453=4|448=ZERO|447=D|452=3|448=MBY2|447=D|452=1|448=LMEB|447=D|452=16|448=DOR|447=D|452=11|826=0|78=1|79=default|80=50000000.00|5967=88330000.00|10=111"
let obj = {};
items = s.split("|")
items.forEach(item=>{
let pair = item.split("=");
obj[pair[0]] = pair[1];
});
let jsonString = JSON.stringify(obj);
Python:
import json
s = "8=FIXT.1.1|9=449|11=ABCD1|35=AE|34=1734|49=REPOFIXUAT|52=20140402-11:38:34|56=TR_UAT_VENDOR|1128=8|15=GBP|31=1.7666|32=50000000.00|55=GBP/USD|60=20140402-11:07:33|63=B|64=20140415|65=OR|75=20140402|150=F|167=FOR|194=1.7654|195=0.0012|460=4|571=7852455|1003=2 USD|1056=88330000.00|1057=N|552=1|54=2|37=20140402-12:36:48|11=NOREF|453=4|448=ZERO|447=D|452=3|448=MBY2|447=D|452=1|448=LMEB|447=D|452=16|448=DOR|447=D|452=11|826=0|78=1|79=default|80=50000000.00|5967=88330000.00|10=111"
obj = {}
for item in s.split("|"):
pair = item.split("=")
obj[pair[0]] = pair[1]
jsonString = json.dumps(obj)
Porting the above solutions to other languages is an exercise for yourself. There's comments below about semantic ordering and handling cases where the the = or | chars are part of the content. That's on you to explore if you need to support those scenarios.
Note: this is a similar but NOT duplicate question with How to use sqlx to query mysql IN a slice?. I'm asking for the Rust one.
This is what I try to do.
let v = vec![..];
sqlx::query("SELECT something FROM table WHERE column IN (?)").bind(v)
...
Then I got the following error
the trait bound `std::vec::Vec<u64>: sqlx::Encode<'_, _>` is not satisfied
Answer is in first on FAQ https://github.com/launchbadge/sqlx/blob/master/FAQ.md
How can I do a SELECT ... WHERE foo IN (...) query? In 0.6 SQLx will
support binding arrays as a comma-separated list for every database,
but unfortunately there's no general solution for that currently in
SQLx itself. You would need to manually generate the query, at which
point it cannot be used with the macros.
The error shows Vec is not an Encode that is required to be as a valid DB value. The Encode doc lists all the Rust types that have implemented the trait. Vec is not one.
You can use the following way to bind the parameters in IN with the values of a vector. Firstly, you need to expand the number of '?' in the IN expression to be the same number of the parameters. Then, you need to call bind to bind the values one by one.
let v = vec![1, 2];
let params = format!("?{}", ", ?".repeat(v.len()-1));
let query_str = format!("SELECT id FROM test_table WHERE id IN ( { } )", params);
let mut query = sqlx::query(&query_str);
for i in v {
query = query.bind(i);
}
let row = query.fetch_all(&pool).await?;
Please note if the target database is not MySql, you need to use $n, like $1, $2, instead of ?, as the parameter placeholder.
I am using mysql-native driver. My code:
ResultRange MySQLTablesRange = mysqlconnection.query(`SELECT historysensor FROM TableName`);
auto historysensor = MySQLTablesRange.array.filter!(a=>a[0].coerce!string.canFind("historysensor"));
But on send string I am getting to historysensor not an array, but structure like: Row([historysensor_10774], [false]).
So every time to get value I need to do a lot of casting like:
foreach(sensor;historysensor)
{
writeln(sensor[0].coerce!string.split("_")[1]);
}
How I can make historysensor as simple array, to be able to work without [0].coerce!string?
You can just map it before doing the other stuff
auto historysensor = MySQLTablesRange.array.
map!(a => a[0].coerce!string). // this is new
filter!(a.canFind("historysensor"). // no need for coerce here now
array; // convert to plain array of strings
BTW using filter here is probably a mistake too, make that part of your query so the database does it, that would be likely more efficient and easier to read.
It is possible to preserve insertion order when parsing a JSON struct with a
Poco::JSON::Parser( new Poco::JSON::ParseHandler( true ) ): the non-default ParseHandler parameter preserveObjectOrder = true is handed over to the Poco::JSON::Objects so that they keep an private list of keys sorted in insertion order.
An object can then be serialized via Object::stringify() to look just like the source JSON string. Fine.
What, however, is the official way to step through a Poco::JSON::Object and access its internals in insertion order? Object::getNames() and begin()/end() use the alphabetical order of keys, not insertion order -- is there another way to access the values, or do I have to patch Poco?
As you already said:
Poco::JSON::ParseHandler goes into the Poco::JSON::Parser-constructor.
Poco::JSON::Parser::parse() creates a Poco::Dynamic::Var.
From that you'll extract a Poco::JSON::Object::Ptr.
The Poco::JSON:Object has the method "getNames". Beginning with this commit it seems to preserve the order, if it was requested via the ParseHandler. (Poco::JSON:Object::getNames 1.8.1, Poco::JSON:Object::getNames 1.9.0)
So now it should work as expected to use:
for(auto const & name : object->getNames()){
auto const & value = object->get(name); // or one of the other get-methods
// ... do things ...
}
I am using Play 2.2.x with Slick 2.0 (with MYSQL backend) to write a REST API. I have a User model with bunch of fields like age, name, gender etc. I want to create a route PATCH /users/:id which takes in partial user object (i.e. a subset of the fields of a full user model) in the body and updates the user's info. I am confused how I can achieve this:
How do I use PATCH verb in Play 2.2.x?
What is a generic way to parse the partial user object into an update query to execute in Slick 2.0?I am expecting to execute a single SQL statement e.g. update users set age=?, dob=? where id=?
Disclaimer: I haven't used Slick, so am just going by their documentation about Plain SQL Queries for this.
To answer your first question:
PATCH is just-another HTTP verb in your routes file, so for your example:
PATCH /users/:id controllers.UserController.patchById(id)
Your UserController could then be something like this:
val possibleUserFields = Seq("firstName", "middleName", "lastName", "age")
def patchById(id:String) = Action(parse.json) { request =>
def addClause(fieldName:String) = {
(request.body \ fieldName).asOpt[String].map { fieldValue =>
s"$fieldName=$fieldValue"
}
}
val clauses = possibleUserFields.flatMap ( addClause )
val updateStatement = "update users set " + clauses.mkString(",") + s" where id = $id"
// TODO: Actually make the Slick call, possibly using the 'sqlu' interpolator (see docs)
Ok(s"$updateStatement")
}
What this does:
Defines the list of JSON field names that might be present in the PATCH JSON
Defines an Action that will parse the incoming body as JSON
Iterates over all of the possible field names, testing whether they exist in the incoming JSON
If so, adds a clause of the form fieldname=<newValue> to a list
Builds an SQL update statement, comma-separating each of these clauses as required
I don't know if this is generic enough for you, there's probably a way to get the field names (i.e. the Slick column names) out of Slick, but like I said, I'm not even a Slick user, let alone an expert :-)