I am in the process of learning NodeJs and stumbled across this line of code:
var irsdk = require('../');
I cannot figure out what is being loaded. I can see where the variable is being used and calling functions.
I understand how to use the require statement when loading a particular file.
If anyone could shed some light it would be appreciated.
Thanks.
From Node's documentation on Modules
require(X) from module at path Y
1. If X is a core module,
a. return the core module
b. STOP
2. If X begins with './' or '/' or '../'
a. LOAD_AS_FILE(Y + X)
b. LOAD_AS_DIRECTORY(Y + X)
3. LOAD_NODE_MODULES(X, dirname(Y))
4. THROW "not found"
LOAD_AS_FILE(X)
1. If X is a file, load X as JavaScript text. STOP
2. If X.js is a file, load X.js as JavaScript text. STOP
3. If X.json is a file, parse X.json to a JavaScript Object. STOP
4. If X.node is a file, load X.node as binary addon. STOP
LOAD_AS_DIRECTORY(X)
1. If X/package.json is a file,
a. Parse X/package.json, and look for "main" field.
b. let M = X + (json main field)
c. LOAD_AS_FILE(M)
2. If X/index.js is a file, load X/index.js as JavaScript text. STOP
3. If X/index.json is a file, parse X/index.json to a JavaScript object. STOP
4. If X/index.node is a file, load X/index.node as binary addon. STOP
LOAD_NODE_MODULES(X, START)
1. let DIRS=NODE_MODULES_PATHS(START)
2. for each DIR in DIRS:
a. LOAD_AS_FILE(DIR/X)
b. LOAD_AS_DIRECTORY(DIR/X)
NODE_MODULES_PATHS(START)
1. let PARTS = path split(START)
2. let I = count of PARTS - 1
3. let DIRS = []
4. while I >= 0,
a. if PARTS[I] = "node_modules" CONTINUE
c. DIR = path join(PARTS[0 .. I] + "node_modules")
b. DIRS = DIRS + DIR
c. let I = I - 1
5. return DIRS
require('../') runs the LOAD_AS_DIRECTORY(X) section for the parent directory.
To make this simple, just keep in mind that if you dont specify a file but a directory, it will be the index.js file that will be loaded.
In the current case, we are requiring ../ witch will load the index of the upper directory.
It could be the InRule SDK for JS (http://www.inrule.com/products/inrule-for-javascript/) Which can be used to separate your business logic out from your application logic.
Or, it could be the npm 'node-irsdk' package which appears to be a telemetry package of some sort that enhances the existing "utils" module. (https://www.npmjs.com/package/node-irsdk)
Either way, you can log it out to the console to get more information about it by literally logging the variable.
console.log(irsdk);
//or
console.dir(irsdk);
//both must be called AFTER you instantiate the var irsdk = req.....
Related
aprx = arcpy.mp.ArcGISProject("CURRENT")
m = aprx.listMaps("Map")[0]
for lyr in m.listLayers("POP_ACS17"):
if lyr.supports("DEFINITIONQUERY"):
for value in listnumbers.split(','):
lyr.definitionQuery = "COLUMN=" + num
output_path=r'C:/ArcGIS/Projects/Value_by_Value/'+ num
arcpy.FeatureClassToShapefile_conversion('POP_ACS17',output_path)
How do i create a shapefile name in the folder based on the query result, and not the same name "POP_ACS17" multiple times? Instead something like num + "_POPACS17" and so on. When i type
arcpy.FeatureClasstoShapefile_conversion('POP_ACS17', num + "_"+ outputh_path)
it does not work. i get an error message
ERROR 000732: Output Folder: Dataset C:/ArcGIS/Projects/Value_by_Value/1.0/1.0_PCT_POP_ACS17 does not exist or is not supported
All I want to do is just have my output renamed by the corresponding value in the loop underscore and the default name that it already gives which is 'POP_ACS17'
so i want
1.0_POP_ACS17.shp in folder 1.0
2.0_POP_ACS17.shp in folder 2.0
3.0_POP_ACS17.shp in folder 3.0
if not then
POP_ACS17_1.0 in folder 1.0
POP_ACS17_2.0 in folder 2.0
POP_ACS17_3.0 in folder 3.0
and so on... It does not matter which order as long as I know how this can be done.
Instead of
arcpy.FeatureClassToShapefile_conversion('PCT_POP_ACS17', output_path)
do.....
arcpy.FeatureClassToFeatureClass_conversion("_PCT_POP_ACS17", output_path, value+"_PCT_POP_ACS17.shp")
make sure you add .shp otherwise each output will appear in your project file.
I need to do some file operations with paths relative to the script that required the current one.
Say we have the following in ~/somewhere/file2.js
const y = require('~/file1.js');
And in ~/file1.js we have:
const x = require('./other/script.js'); //relative to ~/file1.js
And we invoke it like this:
cd ~/somedir
node ~/somewhere/file2.js
then within ~/other/script.js we can do this:
console.log(__dirname); // -> ~/other
console.log(__filename); // -> ~/other/script.js
console.log(process.cwd()); // -> ~/somedir
console.log(process.argv[0]); // -> path/to/node
console.log(path.resolve('.')); // -> ~/somedir
console.log(process.argv[1]); // -> ~/somewhere/file2.js
None of these are the path I need.
How, from ~other/script.js, can I determine the location of the script that required us - i.e ~/file1.js
To put it another way.
~/somewhere/file2.js requires ~/file1.js
and
~/file1.js requires ~/other/script.js
from within ~/other/script.js I need to do file operations relative to ~/somewhere/file1.js - how can I get it's location?
I actually only need the directory in which file1.js sits, so filename or directory will work for me.
You can use module.parent.filename inside of other/script.js, or you can pass the __dirname as a parameter to your module like require('other/script.js')(__dirname) (given your module exports a function)
Haskell package Cabal-1.24.2 has module Distribution.PackageDescription.Parse.
Module has 2 functions: readPackageDescription and parsePackageDescription.
When I run in ghci:
let d = readPackageDescription normal "C:\\somefile.cabal"
I got parsed GenericPackageDescription
But when I run in ghci:
content <- readFile "C:\\somefile.cabal"
let d = parsePackageDescription content
I got Parse error:
ParseFailed (FromString "Plain fields are not allowed in between stanzas: F 2 \"version\" \"0.1.0.0\"" (Just 2))
File example is a file that generated using cabal init
parsePackageDescription expects the file contents themselves to be passed it, not the file path they are stored at. You'll want to readFile first... though beware of file encoding issues. http://www.snoyman.com/blog/2016/12/beware-of-readfile
I'm trying to make a system which backs up and restores points for a gameserver, so it can safely restart without loosing anything.
I have made a script to do just this and the actual backing up part works fine, but the restore part does not.
This is the script that runs if 'Backup(read)' is used (Backup(write) works perfectly as it is designed to do):
if (source and read) then
System.LogAlways("[System] Restoring serverdata from file 'backup.CHK'");
for line in source:lines() do
Backup = {};
Backup.Date = (Date or line:match("File Last Modified: (.-)"));
Backup.Time = (Time or line:match("time: (.-)"));
US = tonumber((US or line:match("us: (.-)")));
NK = tonumber((NK or line:match("nk: (.-)")));
local params = {class = "Player";
position = {x = 1, y = 1, z = -1000};
Respawn = { bRespawn = 0; nTimer =0; bUnique = 1; };
bUsable = 0;
orientation = {0, 90, 135};
name = "BackupEntity"; };
local ent = System.SpawnEntity(params);
g_gameRules.game:SetTeam(1, ent.id);
g_gameRules.game:SetSynchedEntityValue(playerId, 100, (NK/3));
g_gameRules.game:SetTeam(2, ent.id);
g_gameRules.game:SetSynchedEntityValue(playerId, 100, (US/3));
System.RemoveEntity(params);
end
source:close();
return;
end
I'm not sure what I'm doing wrong,and most sites that I have looked at don't help that much. The problem is that it's not reading any values from the file.
Any help will be appreciated :).
Edit:
The reason that we have to divide the score by 3 is because the server multiplies all scores by 3. If we were not to divide it by 3, then the score will always be 3 times larger on each restore.
Example contents of the backup.CHK file:
The server is dependent on this file, and writes to it every hour. Please do not edit.
File Last Modified: 11/07/2013
This file was generated by the servers' autobackup system.
--------------------------
time: 22:51
us: 453445
nk: 454567
A couple of ideas of what might be causing the problem:
Use of (.-) lazy matching which matches the shortest pattern possible -- this can include an empty string. Usually, you want to make the pattern as specific as possible while still matching the required possible inputs. eg. It looks like (%d+) for us and nk is an appropriate fit.
The for line in source:lines() do reads one line at a time. That necessarily means not all the variables are going to be set inside the loop. Yet everything starting at local params and down uses those variables as if they were. It seems to me that section of code shouldn't even be in the loop.
Lastly, have you considered saving the Backup file as just another lua file? Doing so means you can let lua do the heavy lifting for you and you won't have to bother parsing it yourself. That also minimizes the risk for error.
I'm looking to monkey-patch require() to replace its file loading with my own function. I imagine that internally require(module_id) does something like:
Convert module_id into a file path
Load the file path as a string
Compile the string into a module object and set up the various globals correctly
I'm looking to replace step 2 without reimplementing steps 1 + 3. Looking at the public API, there's require() which does 1 - 3, and require.resolve() which does 1. Is there a way to isolate step 2 from step 3?
I've looked at the source of require mocking tools such as mockery -- all they seem to be doing is replacing require() with a function that intercepts certain calls and returns a user-supplied object, and passes on other calls to the native require() function.
For context, I'm trying to write a function require_at_commit(module_id, git_commit_id), which loads a module and any of that module's requires as they were at the given commit.
I want this function because I want to be able to write certain functions that a) rely on various parts of my codebase, and b) are guaranteed to not change as I evolve my codebase. I want to "freeze" my code at various points in time, so thought this might be an easy way of avoiding having to package 20 copies of my codebase (an alternative would be to have "my_code_v1": "git://..." in my package.json, but I feel like that would be bloated and slow with 20 versions).
Update:
So the source code for module loading is here: https://github.com/joyent/node/blob/master/lib/module.js. Specifically, to do something like this you would need to reimplement Module._load, which is pretty straightforward. However, there's a bigger obstacle, which is that step 1, converting module_id into a file path, is actually harder than I thought, because resolveFilename needs to be able to call fs.exists() to know where to terminate its search... so I can't just substitute out individual files, I have to substitute entire directories, which means that it's probably easier just to export the entire git revision to a directory and point require() at that directory, as opposed to overriding require().
Update 2:
Ended up using a different approach altogether... see answer I added below
You can use the require.extensions mechanism. This is how the coffee-script coffee command can load .coffee files without ever writing .js files to disk.
Here's how it works:
https://github.com/jashkenas/coffee-script/blob/1.6.2/lib/coffee-script/coffee-script.js#L20
loadFile = function(module, filename) {
var raw, stripped;
raw = fs.readFileSync(filename, 'utf8');
stripped = raw.charCodeAt(0) === 0xFEFF ? raw.substring(1) : raw;
return module._compile(compile(stripped, {
filename: filename,
literate: helpers.isLiterate(filename)
}), filename);
};
if (require.extensions) {
_ref = ['.coffee', '.litcoffee', '.md', '.coffee.md'];
for (_i = 0, _len = _ref.length; _i < _len; _i++) {
ext = _ref[_i];
require.extensions[ext] = loadFile;
}
}
Basically, assuming your modules have a set of well-known extensions, you should be able to use this pattern of a function that takes the module and filename, does whatever loading/transforming you need, and then returns an object that is the module.
This may or may not be sufficient to do what you are asking, but honestly from your question it sounds like you are off in the weeds somewhere far from the rest of the programming world (don't take that harshly, it's just my initial reaction).
So rather than mess with the node require() module, what I ended up doing is archiving the given commit I need to a folder. My code looks something like this:
# commit_id is the commit we want
# (note that if we don't need the whole repository,
# we can pass "commit_id path_to_folder_we_need")
#
# path is the path to the file you want to require starting from the repository root
# (ie 'lib/module.coffee')
#
# cb is called with (err, loaded_module)
#
require_at_commit = (commit_id, path, cb) ->
dir = 'old_versions' #make sure this is in .gitignore!
dir += '/' + commit_id
do_require = -> cb null, require dir + '/' + path
if not fs.existsSync(dir)
fs.mkdirSync(dir)
cmd = 'git archive ' + commit_id + ' | tar -x -C ' + dir
child_process.exec cmd, (error) ->
if error
cb error
else
do_require()
else
do_require()