System environment : Windows 7(64bit), VS 2013, Compile in release 64bit
This is the code:
var clients = new ZSocket(ctx, ZSocketType.ROUTER);
clients.GetOptionString(ZSocketOption.TCP_KEEPALIVE));
Exception as below:
ZeroMQ.ZException ""EINVAL(22): Invalid argument""
EINVAL ( Error: 22 ) was thrown correctly:
EINVAL
The requested option option_name is unknown, or the requested option_len or option_value is invalid, or the size of the buffer pointed to by option_value, as specified by option_len, is insufficient for storing the option value.
Must fix both of the below listed API non-compliant issues:
The ZeroMQ API defines the ZMQ_TCP_KEEPALIVE socket-configuration option to be of an int data type, not a string. Use the appropriate clrzmq4 binding interface function to request an int typed option_value and this first API incompliance will be solved.
Option value type int
Option value unit { -1 | 0 | 1 }
Default value -1 ( leave to OS default )
Applicable socket types all, when using TCP transports.
The ZeroMQ API defines this option to be valid if and only if the socket-instance was equipped with a tcp:// transport-class ( which the clients instance, as posted above, was not ). May defer the request to take place after the socket-instance has been instructed to associate a first tcp:// transport-class engine ( be it via a respective use of a .connect() or a .bind() ).
Related
I am using protobuf with version3 in Php. Below is my proto file
syntax ="proto3";
package message.events.user.v1;
message UserWasActivatedMessage {
int32 userId = 1 ;
string eventType = 2;
}
This is my proto file and whenever I do not set any user or event proto is automatically setting them up with a default value which I do not want, now I want user to explicitly define every value whenever they send a message as this will reduce the chance of not defining any value
This is a "feature" of protocol buffers and cannot be overriden using the standard SDKs. See:
https://developers.google.com/protocol-buffers/docs/proto3#default
I assume the requirement of having default values is a result of the schemaless nature of on-the-wire messages, where all fields must be included and there being no way to specify a value as nil.
Yes, there's a difference in meaning between nil and default but you can't reflect that in protocol buffers.
Looking at the source code c.Organizations = (*OrganizationsService)(&c.common) from https://github.com/google/go-github/blob/master/github/github.go#L283, in describing this bit of code with proper terminology, would you describe it as follows:
The Organizations field of variable c is set to the address of c.common casted to a pointer receiver value of OrganizationsService.
Or am I missing a bit of nuance when describing this?
Below are some relevant bits of source code that show where the variables are being defined.
// A Client manages communication with the GitHub API.
type Client struct {
clientMu sync.Mutex // clientMu protects the client during calls that modify the CheckRedirect func.
client *http.Client // HTTP client used to communicate with the API.
// Base URL for API requests. Defaults to the public GitHub API, but can be
// set to a domain endpoint to use with GitHub Enterprise. BaseURL should
// always be specified with a trailing slash.
BaseURL *url.URL
// Base URL for uploading files.
UploadURL *url.URL
// User agent used when communicating with the GitHub API.
UserAgent string
rateMu sync.Mutex
rateLimits [categories]Rate // Rate limits for the client as determined by the most recent API calls.
common service // Reuse a single struct instead of allocating one for each service on the heap.
// Services used for talking to different parts of the GitHub API.
Actions *ActionsService
Activity *ActivityService
Admin *AdminService
Apps *AppsService
Authorizations *AuthorizationsService
Checks *ChecksService
CodeScanning *CodeScanningService
Enterprise *EnterpriseService
Gists *GistsService
Git *GitService
Gitignores *GitignoresService
Interactions *InteractionsService
IssueImport *IssueImportService
Issues *IssuesService
Licenses *LicensesService
Marketplace *MarketplaceService
Migrations *MigrationService
Organizations *OrganizationsService
Projects *ProjectsService
PullRequests *PullRequestsService
Reactions *ReactionsService
Repositories *RepositoriesService
Search *SearchService
Teams *TeamsService
Users *UsersService
}
type service struct {
client *Client
}
The Organizations field of variable c is set to the address of c.common casted to a pointer receiver value of OrganizationsService.
This is close, but I'd make a few changes.
First:
casted
The operation being done here, according to official Go terminology, is a "conversion" not a cast.
Second:
c is set to the address of c.common...
While & is the "addressing" operator, the value that it results in is a pointer value. The literal contents of that value is the address. It's not incorrect to refer to addresses, but while analyzing syntax and structure, we would probably rather refer to values at the high level, rather than the contents of them.
Third:
pointer receiver value of...
The word "receiver" in Go refers to the receiver value in method call or method declaration, e.g.
func (v *Value) Method() {
}
Here v is the receiver, and it's type does happen to be a pointer type, but it doesn't have to be.
func (v Value) Method() {
}
This is also valid (though may have different and unintended effects compared to the first version). Regardless, the value in your question is not a receiver in any sense.
With the adjustments:
The Organizations field of variable c is set to the pointer to c.common converted to a pointer value to the OrganizationsService type.
Even still, we could restructure the sentence a bit so it is more similar to the order of operations as they happen in the program. It may seem natural to analyze things from left to right, but this is rarely the most comprehensible expression of code.
Here's an explanation that is, in my opinion, more natural.
The pointer to c's "common" field is converted to a pointer to OrganizationsService, and then assigned to c's "Organizations" field.
The Q&A is currently a subject of meta discussion, do participate. The current plan is to split where possible into Q&As. Answers to the A&A are community wiki and the question should become one when the status is resolved.
Preface
This Q&A strives to become a collection and a reference target for common errors encountered during development in Google Apps Script language in hopes to improve long-term maintainability of google-apps-script tag.
There are several similar and successful undergoings in other languages and general-purpose tags (see c++, android, php, php again), and this one follows suit.
Why it exists?
The amount of questions from both new and experienced developers regarding the meaning and solutions to errors encountered during development and production that can be effectively reduced to a single answer is substantial. At the time of writing, even running a query only by language tag yields:
"Cannot find method" 8 pages
"Cannot read property" 9 pages
"Cannot call ... in this context" 5 pages
"You do not have permission" 11 pages
Linking to a most relevant duplicate is hard and time-consuming for volunteers due to the need to consider nuances and often poorly-worded titles.
What it consists of?
Entries in this Q&A contain are designed to provide info on how to:
parse the error message structure
understand what the error entails
consistently reproduce (where applicable)
resolve the issue
provide a link to canonical Q&A (where possible)
Table of Contents
To help you navigate the growing reference please use the TOC below:
General errors
Service-specific errors
What this is not?
The scope of the Q&A is limited to common (not trivial). This is not:
a catch-all guide or "best practices" collection
a reference for general ECMAScript errors
GAS documentation
a resources list (we have a tag wiki for that)
What to add?
When adding an entry, please, consider the following:
is the error common enough (see "why" section for examples)?
can the solution be described concisely and be applicable for most cases?
Preface
The answer provides a guide on general errors that can be encountered when working with any Google service (both built-in and advanced) or API. For errors specific to certain services, see the other answer.
Back to reference
General errors
Message
TypeError: Cannot read property 'property name here' from undefined (or null)
Description
The error message indicates that you are trying to access a property on an Object instance, but during runtime the value actually held by a variable is a special data type undefined. Typically, the error occurs when accessing nested properties of an object.
A variation of this error with a numeric value in place of property name indicates that an instance of Array was expected. As arrays in JavaScript are objects, everything mentioned here is true about them as well.
There is a special case of dynamically constructed objects such as event objects that are only available in specific contexts like making an HTTP request to the app or invoking a function via time or event-based trigger.
The error is a TypeError because an "object" is expected, but "undefined" is received
How to fix
Using default values
Logical OR || operator in JavaScript has an intersting property of evaluating the right-hand side iff the left-hand is falsy. Since objects in JS are truthy, and undefined and null are falsy, an expression like (myVar || {}).myProp [(myVar || [])[index] for arrays] will guarantee that no error is thrown and the property is at least undefined.
One can also provide default values: (myVar || { myProp : 2 }) guarantees accessing myProp to return 2 by default. Same goes for arrays: (myVar || [1,2,3]).
Checking for type
Especially true for the special case, typeof operator combined with an if statement and a comparison operator will either allow a function to run outside of its designated context (i.e. for debugging purposes) or introduce branching logic depending on whether the object is present or not.
One can control how strict the check should be:
lax ("not undefined"): if(typeof myVar !== "undefined") { //do something; }
strict ("proper objects only"): if(typeof myVar === "object" && myVar) { //do stuff }
Related Q&As
Parsing order of the GAS project as the source of the issue
Message
Cannot convert some value to data type
Description
The error is thrown due to passing an argument of different type than a method expects. A common mistake that causes the error is accidental coercion of a number to string.
How to reproduce
function testConversionError() {
const ss = SpreadsheetApp.getActiveSheet();
ss.getRange("42.0",1);
}
How to fix
Make sure that the value referenced in the error message is of data type required by documentation and convert as needed.
Message
Cannot call Service and method name from this context
Description
This error happens on a context mismatch and is specific to container-bound scripts.
The primary use case that results in the error is trying to call a method only available in one document type (usually, getUi() as it is shared by several services) from another (i.e. DocumentApp.getUi() from a spreadsheet).
A secondary, but also prominent case is a result of calling a service not explicitly allowed to be called from a custom function (usually a function marked by special JSDoc-style comment #customfunction and used as a formula).
How to reproduce
For bound script context mismatch, declare and run this function in a script project tied to Google Sheets (or anything other than Google Docs):
function testContextMismatch() {
const doc = DocumentApp.getUi();
}
Note that calling a DocumentApp.getActiveDocument() will simply result in null on mismatch, and the execution will succeed.
For custom functions, use the function declared below in any cell as a formula:
/**
* #customfunction
*/
function testConversionError() {
const ui = SpreadsheetApp.getUi();
ui.alert(`UI is out of scope of custom function`);
}
How to fix
Context mismatch is easily fixed by changing the service on which the method is called.
Custom functions cannot be made to call these services, use custom menus or dialogs.
Message
Cannot find method Method name here
The parameters param names do not match the method signature for method name
Description
This error has a notoriously confusing message for newcomers. What it says is that a type mismatch occurred in one or more of the arguments passed when the method in question was called.
There is no method with the signature that corresponds to how you called it, hence "not found"
How to fix
The only fix here is to read the documentation carefully and check if order and inferred type of parameters are correct (using a good IDE with autocomplete will help). Sometimes, though, the issue happens because one expects the value to be of a certain type while at runtime it is of another. There are several tips for preventing such issues:
Setting up type guards (typeof myVar === "string" and similar).
Adding a validator to fix the type dynamically thanks to JavaScript being dynamically typed.
Sample
/**
* #summary pure arg validator boilerplate
* #param {function (any) : any}
* #param {...any} args
* #returns {any[]}
*/
const validate = (guard, ...args) => args.map(guard);
const functionWithValidator = (...args) => {
const guard = (arg) => typeof arg !== "number" ? parseInt(arg) : arg;
const [a,b,c] = validate(guard, ...args);
const asObject = { a, b, c };
console.log(asObject);
return asObject;
};
//driver IIFE
(() => {
functionWithValidator("1 apple",2,"0x5");
})()
Messages
You do not have permission to perform that action
The script does not have permission to perform that action
Description
The error indicates that one of the APIs or services accessed lacks sufficient permissions from the user. Every service method that has an authorization section in its documentation requires at least one of the scopes to be authorized.
As GAS essentially wraps around Google APIs for development convenience, most of the scopes listed in OAuth 2.0 scopes for APIs reference can be used, although if one is listed in the corresponding docs it may be better to use it as there are some inconsistencies.
Note that custom functions run without authorization. Calling a function from a Google sheet cell is the most common cause of this error.
How to fix
If a function calling the service is ran from the script editor, you are automatically prompted to authorize it with relevant scopes. Albeit useful for quick manual tests, it is best practice to set scopes explicitly in application manifest (appscript.json). Besides, automatic scopes are usually too broad to pass the review if one intends to publish the app.
The field oauthScopes in manifest file (View -> Show manifest file if in code editor) should look something like this:
"oauthScopes": [
"https://www.googleapis.com/auth/script.container.ui",
"https://www.googleapis.com/auth/userinfo.email",
//etc
]
For custom functions, you can fix it by switching to calling the function from a menu or a button as custom functions cannot be authorized.
For those developing editor Add-ons, this error means an unhandled authorization lifecycle mode: one has to abort before calls to services that require authorization in case auth mode is AuthMode.NONE.
Related causes and solutions
#OnlyCurrentDoc limiting script access scope
Scopes autodetection
Message
ReferenceError: service name is not defined
Description
The most common cause is using an advanced service without enabling it. When such a service is enabled, a variable under the specified identifier is attached to global scope that the developer can reference directly. Thus, when a disabled service is referenced, a ReferenceError is thrown.
How to fix
Go to "Resources -> Advanced Google Services" menu and enable the service referenced. Note that the identifier should equal the global variable referenced.
For a more detailed explanation, read the official guide.
If one hasn't referenced any advanced services then the error points to an undeclared variable being referenced.
Message
The script completed but did not return anything.
Script function not found: doGet or doPost
Description
This is not an error per se (as the HTTP response code returned is 200 and the execution is marked as successful, but is commonly regarded as one. The message appears when trying to make a request/access from browser a script deployed as a Web App.
There are two primary reasons why this would happen:
There is no doGet or doPost trigger function
Triggers above do not return an HtmlOutput or TextOutput instance
How to fix
For the first reason, simply provide a doGet or doPost trigger (or both) function. For the second, make sure that all routes of your app end with creation of TextOutput or HtmlOutput:
//doGet returning HTML
function doGet(e) {
return HtmlService.createHtmlOutput("<p>Some text</p>");
}
//doPost returning text
function doPost(e) {
const { parameters } = e;
const echoed = JSON.stringify(parameters);
return ContentService.createTextOutput(echoed);
}
Note that there should be only one trigger function declared - treat them as entry points to your application.
If the trigger relies on parameter / parameters to route responses, make sure that the request URL is structured as "baseURL/exec?query" or "baseURL/dev?query" where query contains parameters to pass.
Related Q&As
Redeploying after declaring triggers
Message
We're sorry, a server error occurred. Please wait a bit and try again.
Description
This one is the most cryptic error and can occur at any point with nearly any service (although DriveApp usage is particularly susceptible to it). The error usually indicates a problem on Google's side that either goes away in a couple of hours/days or gets fixed in the process.
How to fix
There is no silver bullet for that one and usually, there is nothing you can do apart from filing an issue on the issue tracker or contacting support if you have a GSuite account. Before doing that one can try the following common remedies:
For bound scripts - creating a new document and copying over the existing project and data.
Switch to using an advanced Drive service (always remember to enable it first).
There might be a problem with a regular expression if the error points to a line with one.
Don't bash your head against this error - try locating affected code, file or star an issue and move on
Syntax error without apparent issues
This error is likely to be caused by using an ES6 syntax (for example, arrow functions) while using the deprecated Rhino runtime (at the time of writing the GAS platform uses V8).
How to fix
Open "appscript.json" manifest file and check if runtimeVersion is set to "V8", change it if not, or remove any ES6 features otherwise.
Quota-related errors
There are several errors related to quotas imposed on service usage. Google has a comprehensive list of those, but as a general rule of thumb, if a message matches "too many" pattern, you are likely to have exceeded the respective quota.
Most likely errors encountered:
Service invoked too many times: service name
There are too many scripts running
Service using too much computer time for one day
This script has too many triggers
How to fix
In most cases, the only fix is to wait until the quota is refreshed or switch to another account (unless the script is deployed as a Web App with permission to "run as me", in which case owner's quotas will be shared across all users).
To quote documentation at the time:
Daily quotas are refreshed at the end of a 24-hour window; the exact time of this refresh, however, varies between users.
Note that some services such as MailApp have methods like getRemainingDailyQuota that can check the remaining quota.
In the case of exceeding the maximum number of triggers one can check how many are installed via getProjectTriggers() (or check "My triggers" tab) and act accordingly to reduce the number (for example, by using deleteTrigger(trigger) to get rid of some).
Related canonical Q&As
How are daily limitations being applied and refreshed?
"Maximum execution time exceeded" problem
Optimizing service calls to reduce execution time
References
How to make error messages more meaningful
Debugging custom functions
Service-specific errors
The answer concerns built-in service-related errors. For general reference see the other answer. Entries addressing issues with services listed in official reference are welcome.
Back to reference
SpreadsheetApp
The number of rows in the range must be at least 1
This error is usually caused by calling the getRange method where the parameter that sets the number of rows happens to equal to 0. Be careful if you depend on getLastRow() call return value - only use it on non-empty sheets (getDataRange will be safer).
How to reproduce
sh.getRange(1, 1, 0, sh.getLastColumn()); //third param is the number of rows
How to fix
Adding a guard that prevents the value from ever becoming 0 should suffice. The pattern below defaults to the last row with data (optional if you only need a certain number of rows) and to 1 if that also fails:
//willFail is defined elsewhere
sh.getRange(1, 1, willFail || sh.getLastRow() || 1, sh.getLastColumn());
Error: “Reference does not exist”
The error happens when calling a custom function in a spreadsheet cell that does not return a value. The docs do mention only that one "must return a value to display", but the catch here is that an empty array is also not a valid return value (no elements to display).
How to reproduce
Call the custom function below in any Google Sheets spreadsheet cell:
/**
* #customfunction
*/
const testReferenceError = () => [];
How to fix
No specific handling is required, just make sure that length > 0.
The number of rows or cells in the data does not match the number of rows or cells in the range. The data has N but the range has M.
Description
The error points to a mismatch in dimensions of range in relation to values. Usually, the issue arises when using setValues() method when the matrix of values is smaller or bigger than the range.
How to reproduce
function testOutOfRange() {
const ss = SpreadsheetApp.getActiveSpreadsheet();
const sh = ss.getActiveSheet();
const rng = sh.getActiveRange();
const vals = rng.getValues();
try {
vals.push([]);
rng.setValues(vals);
} catch (error) {
const ui = SpreadsheetApp.getUi();
ui.alert(error.message);
}
}
How to fix
If it is routinely expected for values to get out of bounds, implement a guard that catches such states, for example:
const checkBounds = (rng, values) => {
const targetRows = rng.getHeight();
const targetCols = rng.getWidth();
const { length } = values;
const [firstRow] = values;
return length === targetRows &&
firstRow.length === targetCols;
};
The coordinates of the range are outside the dimensions of the sheet.
Description
The error is a result of a collision between two issues:
The Range is out of bounds (getRange() does not throw on requesting a non-existent range)
Trying to call a method on a Range instance referring to a non-existent dimension of the sheet.
How to reproduce
function testOB() {
const ss = SpreadsheetApp.getActiveSpreadsheet();
const sh = ss.getActiveSheet();
const rng = sh.getRange(sh.getMaxRows() + 1, 1);
rng.insertCheckboxes();
}
How to fix
Check that number of rows (getMaxRow()) and columns (getMaxColumns()) are both greater or equal to the parameters passed to getRange() method call and change them accordingly.
Exception: You can't create a filter in a sheet that already has a filter.
Description
The message means that you are trying to call a createFilter method on a Range in a Sheet that already has a filter set (either via UI or script), thus violating the restriction on 1 filter per Sheet, to quote the documentation:
There can be at most one filter in a sheet.
How to reproduce
const testFilterExistsError = () => {
const sh = SpreadsheetApp.getActiveSheet();
const rng = sh.getDataRange();
const filter1 = rng.createFilter();
const filter2 = rng.createFilter();
};
How to fix
Add a guard that checks for the existence of the filter first. getFilter returns either a filter or null if called on a Range instance and is perfect for the job:
const testFilterGuard = () => {
const sh = SpreadsheetApp.getActiveSheet();
const rng = sh.getDataRange();
const filter = rng.getFilter() || rng.createFilter();
//do something useful;
};
UrlFetchApp
Attribute provided with no value: url
Description
The error is specific to UrlFetchApp service and happens when fetch or fetchAll method gets called with an empty string or non-string value.
How to reproduce
const response = UrlFetchApp.fetch("", {});
How to fix
Make sure that a string containing a URI (not necessarily valid) is passed to the method as its first argument. As its common root cause is accessing a non-existent property on an object or array, check whether your accessors return an actual value.
I'm trying to connect to a remote host to issue a command, but I'm getting the following error message while running the code:
ssh: handshake failed: ssh: no common algorithm for key exchange; client offered: [curve25519-sha256#libssh.org ecdh-sha2-nistp256 ecdh-sha2-nistp384 ecdh-sha2-nistp521 diffie-hellman-group14-sha1], server offered: [diffie-hellman-group1-sha1]panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x10 pc=0x759836]
Here is the code that I'm using:
func (SSHClient *SSH) Connect(mode int) {
var SSHConfig *ssh.ClientConfig
var auth []ssh.AuthMethod
if mode == CERT_PUBLIC_KEY_FILE {
auth = []ssh.AuthMethod{SSHClient.readPublicKeyFile(SSHClient.Cert)}
}
SSHConfig = &ssh.ClientConfig{
User: SSHClient.User,
Auth: auth,
HostKeyCallback: ssh.InsecureIgnoreHostKey(),
Timeout: time.Second * DEFAULT_TIMEOUT,
}
SSHConfig.Config.Ciphers = append(SSHConfig.Config.Ciphers, "diffie-hellman-group1-sha1")
client, err := ssh.Dial("tcp", fmt.Sprintf("%s:%d", SSHClient.IP, SSHClient.Port), SSHConfig)
if err != nil {
fmt.Printf("ERROR - While trying to Dial to the host %s with error: %s", SSHClient.IP, err.Error())
return
}
session, err := client.NewSession()
if err != nil {
fmt.Printf("ERROR - While trying to create a new session on host %s with error: %s", SSHClient.IP, err.Error())
client.Close()
return
}
SSHClient.session = session
SSHClient.client = client
}
Any ideas on how to resolve this issue?
Thanks in advance.
The problem is.... the server is only willing to talk over diffie-hellman-group1-sha1
And:
golang/go issue 2903: ssh: add diffie-hellman-group1-sha1, has been closed 6 days ago
golang/go/issue 17230: proposal: x/crypto/ssh: support Diffie-Hellman Group Exchange from RFC 4419, is being implemented now.
So you would need for your client a fork of golang.org/x/crypto/ssh, like bored-engineer/ssh, where commit 39a91b and commit fe5e4ff does add support for diffie-hellman-group1-sha1.
Or install the latest of golang/crypto, which includes commit 57b3e21.
The panic is somewhat strange. Clearly something goes wrong when no key exchange algorithm can be agreed-to. As VonC notes, Diffie-Hellman key exchange was only added fairly recently (June 3). Since your server offers only that algorithm, you can't get started without it.
This is not the cause of the panic (which seems to happen inside ssh.Dial itself), but I will note that when you do this:
SSHConfig.Config.Ciphers = append(SSHConfig.Config.Ciphers, "diffie-hellman-group1-sha1")
you wind up telling the Go code to only use diffie-hellman-group1-sha1 as the channel encryption. You do not add to anything here. The reason is that SSHConfig.Config.Ciphers is initially nil. So you might as well write:
SSHConfig.Config.Ciphers = []string{"diffie-hellman-group1-sha1"}
to get the same effect, which is: things won't work.
You can call SetDefaults so that the list is non-empty before adding to the list, but adding to the list is ineffective if there is no implementation for this mode—and even with the new commits, Diffie-Hellman isn't allowed for anything other than the key exchange itself. Note that ssh.Dial calls ssh.NewClientConn, which is here and which starts with:
fullConf := *config
fullConf.SetDefaults()
SetDefaults in turn is here and contains:
if c.Ciphers == nil {
c.Ciphers = preferredCiphers
}
var ciphers []string
for _, c := range c.Ciphers {
if cipherModes[c] != nil {
// reject the cipher if we have no cipherModes definition
ciphers = append(ciphers, c)
}
}
c.Ciphers = ciphers
which first says that if the config's Ciphers is not set, it should use the defaults, and then immediately after that, filters away any string that's not in cipherModes. This in turn is defined here and starts with this comment:
// cipherModes documents properties of supported ciphers. Ciphers not included
// are not supported and will not be negotiated, even if explicitly requested in
// ClientConfig.Crypto.Ciphers.
This phrase is not in the documentation. It should be! Ciphers not included are not supported and will not be negotiated, even if explicitly requested in ClientConfig.Crypto.Ciphers.
(See the last link above for the set of ciphers that are supported. Note that this list has grown over time.)
Diffie-hellman-group1-sha1 is a key exchange algorithm. Should be KeyExchanges instead of Ciphers in the Config struct
SSHConfig.Config.KeyExchanges = append(SSHConfig.Config.KeyExchanges, "diffie-hellman-group1-sha1")
Instead of
SSHConfig.Config.Ciphers = append(SSHConfig.Config.Ciphers, "diffie-hellman-group1-sha1")
If KeyExchanges is not specified, the default algorithms used can be found in ssh/common.go
// preferredKexAlgos specifies the default preference for key-exchange algorithms
// in preference order.
var preferredKexAlgos = []string{
kexAlgoCurve25519SHA256,
kexAlgoECDH256, kexAlgoECDH384, kexAlgoECDH521,
kexAlgoDH14SHA1,
}
As you can see, kexAlgoDH1SHA1 or diffie-hellman-group1-sha1 is not listed at this time
I have an Go app (web service) which returns errors in json like this:
{errorString: "internal server error"}
It's not ok because "internal server error" is just some programmer error string not usefull for client. The solution is to add error codes:
{errCode: 1, errorString: "internal server error"}
Now, client known that 1 means "internal server error" and can process it as want. For example, show for user message "Internal Server Error" or (in my case) the same in russian lang.
Ok.
So, obviously i need some file where all error constants will be described.
For ex. errors.go
const (
ErrNo = iota
// Common Errors
ErrNotFound
ErrInternalServerError
**// More specified errors**
)
The problem is in More specified errors section.
I have 2 ways:
places all errors definiton in one file errors.go
try to place specific errors to each related file:
my controller is devided on several files in package server:
clienthandler.go -- for client requests,
orderhandler.go -- for orders requests and so on.
specific client errors must be places in clienthandler.go, order errors in orderhandler.go
But how it can be realized?
I know one simple solution:
Take some max count of errors for each controller, for example 1000.
clienthandler.go
package server
const (
ErrCheckIdCity = 1000*1 + iota
ErrCheckName
)
that is 1000 errors (from 1000 to 1999) reserved for this file
orderhandler.go
package server
const (
ErrCheckIdCity = 1000*2 + iota
ErrCheckItem
)
that is 1000 errors (from 2000 to 2999) reserved for this file
But disadvantge is that we limit myself by 1000 errors per controller
May be thers is some better way?
Or i need just use one global errros.go file ) ?
Place each error where it's originated and export it.
See the link from my comment.
var ErrInvalidParam = fmt.Errorf(“invalid parameter [%s]”, param)
If you want to add an error code, create a new type satisfying the error interface and add the appropriate members like errorCode or related data.
If you want, create a build method as helper, similar as errors.New does