Tokens | Ethereum Token Contracts | Cryptocurrency library

 by   ConsenSys JavaScript Version: broken_verifyEIP20 License: MIT

kandi X-RAY | Tokens Summary

kandi X-RAY | Tokens Summary

Tokens is a JavaScript library typically used in Blockchain, Cryptocurrency, Ethereum applications. Tokens has no bugs, it has no vulnerabilities, it has a Permissive License and it has medium support. You can download it from GitHub.

This repo contains Solidity smart contract code for simple, standards-compliant tokens on Ethereum. Adhering to standards allows other contract developers to easily incorporate your token into their applications. The repo currently implements EIP20 tokens, and more may be added in the future.

            kandi-support Support

              Tokens has a medium active ecosystem.
              It has 2004 star(s) with 1198 fork(s). There are 144 watchers for this library.
              It had no major release in the last 6 months.
              There are 14 open issues and 51 have been closed. On average issues are closed in 86 days. There are 8 open pull requests and 0 closed requests.
              It has a neutral sentiment in the developer community.
              The latest version of Tokens is broken_verifyEIP20

            kandi-Quality Quality

              Tokens has 0 bugs and 0 code smells.

            kandi-Security Security

              Tokens has no vulnerabilities reported, and its dependent libraries have no vulnerabilities reported.
              Tokens code analysis shows 0 unresolved vulnerabilities.
              There are 0 security hotspots that need review.

            kandi-License License

              Tokens is licensed under the MIT License. This license is Permissive.
              Permissive licenses have the least restrictions, and you can use them in most projects.

            kandi-Reuse Reuse

              Tokens releases are not available. You will need to build from source code and install.
              Installation instructions are not available. Examples and code snippets are available.

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            Tokens Key Features

            No Key Features are available at this moment for Tokens.

            Tokens Examples and Code Snippets

            Encode tokens .
            javadot img1Lines of Code : 48dot img1no licencesLicense : No License
            copy iconCopy
            private void encodeTokens(ByteArrayOutputStream output) 
            		throws IOException {
            		// read tag name
            		String tagName = nextToken();
            		// read attributes
            		while (!hasNextToken(">") &&a  
            Get all tokens from file
            javadot img2Lines of Code : 16dot img2License : Permissive (MIT License)
            copy iconCopy
            public List getTokensFromFile(String path, String delim) {
                    List tokens = new ArrayList<>();
                    String currLine;
                    StringTokenizer tokenizer;
                    try (BufferedReader br = new BufferedReader(new InputStreamReader(MyTokenize  
            Replaces all tokens in the original string with the given pattern .
            javadot img3Lines of Code : 16dot img3License : Permissive (MIT License)
            copy iconCopy
            public static String replaceTokens(String original, Pattern tokenPattern,
                                                   Function converter) {
                    int lastIndex = 0;
                    StringBuilder output = new StringBuilder();
                    Matcher matcher = tokenPatte  

            Community Discussions


            PIP failed to build package cytoolz
            Asked 2022-Mar-26 at 18:26

            I'm trying to install eth-brownie using 'pipx install eth-brownie' but I get an error saying



            Answered 2022-Jan-02 at 09:59

            I used pip install eth-brownie and it worked fine, I didnt need to downgrade. Im new to this maybe I could be wrong but it worked fine with me.



            How to get Metadata from a Token adress using web3 js on SOLANA
            Asked 2022-Mar-14 at 00:31

            I get a list of tokens own by a publicKey thanks to that method :



            Answered 2021-Nov-14 at 22:45

            Unsure if this fully addresses your issue, but one way that I've fetched metadata for all tokens in a wallet is by using the metaplex library:



            Why does GCC remove the whitespace between the preprocessing tokens?
            Asked 2022-Feb-03 at 20:10

            Sample code:



            Answered 2022-Jan-20 at 14:29

            This is a bug in GCC. C 2018 specifies behavior of the # operator. Paragraph 1 says “Each # preprocessing token in the replacement list for a function-like macro shall be followed by a parameter as the next preprocessing token in the replacement list.” We see this in the #x of #define STR_(x) #x.

            Paragraph 2 says:

            If, in the replacement list, a parameter is immediately preceded by a # preprocessing token, both are replaced by a single character string literal preprocessing token that contains the spelling of the preprocessing token sequence for the corresponding argument. Each occurrence of white space between the argument’s preprocessing tokens becomes a single space character in the character string literal. White space before the first preprocessing token and after the last preprocessing token composing the argument is deleted…

            The X(Y,Y) macro invocation must have resulted in the tokens Y and Y, and we see in #define X(x,y) x y that they would have white space between them.

            White-space in a macro replacement list is significant, per 6.10.3 1, which says:

            Two replacement lists are identical if and only if the preprocessing tokens in both have the same number, ordering, spelling, and white-space separation, where all white-space separations are considered identical.

            Thus, in #define X(x,y) x y, the replacement list should not be considered to be just the two tokens x and y, with white space disregarded. The replacement list is x, white space, and y.

            Further, when the macro is replaced, it is replaced by the replacement list (and hence includes white space), not merely by the tokens in the replacement list, per 6.10.3 10:

            … Each subsequent instance of the function-like macro name followed by a ( as the next preprocessing token introduces the sequence of preprocessing tokens that is replaced by the replacement list in the definition (an invocation of the macro)… Within the sequence of preprocessing tokens making up an invocation of a function-like macro, new-line is considered a normal white-space character.



            MetaMask - RPC Error: Cannot set properties of undefined (setting 'loadingDefaults') error
            Asked 2022-Jan-31 at 15:57

            I'm building a staking function and hitting the following error after giving permission to access my token:

            "MetaMask - RPC Error: Cannot set properties of undefined (setting 'loadingDefaults')"

            Staking function Solidity contract:



            Answered 2021-Dec-20 at 23:01

            Having the same issue while working on the same course as you, maybe try using node 10 and redeploy everything.

            Let me know if that works.



            Possible ODR-violations when using a constexpr variable in the definition of an inline function (in C++14)
            Asked 2022-Jan-12 at 10:38

            (Note! This question particularly covers the state of C++14, before the introduction of inline variables in C++17)

            TLDR; Question
            • What constitutes odr-use of a constexpr variable used in the definition of an inline function, such that multiple definitions of the function violates [basic.def.odr]/6?

            (... likely [basic.def.odr]/3; but could this silently introduce UB in a program as soon as, say, the address of such a constexpr variable is taken in the context of the inline function's definition?)

            TLDR example: does a program where doMath() defined as follows:



            Answered 2021-Sep-08 at 16:34

            In the OP's example with std::max, an ODR violation does indeed occur, and the program is ill-formed NDR. To avoid this issue, you might consider one of the following fixes:

            • give the doMath function internal linkage, or
            • move the declaration of kTwo inside doMath

            A variable that is used by an expression is considered to be odr-used unless there is a certain kind of simple proof that the reference to the variable can be replaced by the compile-time constant value of the variable without changing the result of the expression. If such a simple proof exists, then the standard requires the compiler perform such a replacement; consequently the variable is not odr-used (in particular, it does not require a definition, and the issue described by the OP would be avoided because none of the translation units in which doMath is defined would actually reference a definition of kTwo). If the expression is too complicated, however, then all bets are off. The compiler might still replace the variable with its value, in which case the program may work as you expect; or the program may exhibit bugs or crash. That's the reality with IFNDR programs.

            The case where the variable is immediately passed by reference to a function, with the reference binding directly, is one common case where the variable is used in a way that is too complicated and the compiler is not required to determine whether or not it may be replaced by its compile-time constant value. This is because doing so would necessarily require inspecting the definition of the function (such as std::max in this example).

            You can "help" the compiler by writing int(kTwo) and using that as the argument to std::max as opposed to kTwo itself; this prevents an odr-use since the lvalue-to-rvalue conversion is now immediately applied prior to calling the function. I don't think this is a great solution (I recommend one of the two solutions that I previously mentioned) but it has its uses (GoogleTest uses this in order to avoid introducing odr-uses in statements like EXPECT_EQ(2, kTwo)).

            If you want to know more about how to understand the precise definition of odr-use, involving "potential results of an expression e...", that would be best addressed with a separate question.



            Flutter resizeToAvoidBottomInset true not working with Expanded ListView
            Asked 2022-Jan-10 at 08:46

            The keyboard hides my ListView (GroupedListView). I think it's because of the Expanded Widget.

            My body:



            Answered 2022-Jan-04 at 11:41

            It appears that you are using text fields so it hides data or sometimes it may overflow borders by black and yellow stripes

            better to use SingleChildScrollView and for scrolling direction use scrollDirection with parameters Axis.vertical or Axis.horizontal



            Preferring shift over reduce in parser for language without statement terminators
            Asked 2022-Jan-04 at 06:17

            I'm parsing a language that doesn't have statement terminators like ;. Expressions are defined as the longest sequence of tokens, so 5-5 has to be parsed as a subtraction, not as two statements (literal 5 followed by a unary negated -5).

            I'm using LALRPOP as the parser generator (despite the name, it is LR(1) instead of LALR, afaik). LALRPOP doesn't have precedence attributes and doesn't prefer shift over reduce by default like yacc would do. I think I understand how regular operator precedence is encoded in an LR grammar by building a "chain" of rules, but I don't know how to apply that to this issue.

            The expected parses would be (individual statements in brackets):



            Answered 2022-Jan-04 at 06:17

            The issue you're going to have to confront is how to deal with function calls. I can't really give you any concrete advice based on your question, because the grammar you provide lacks any indication of the intended syntax of functions calls, but the hint that print(5) is a valid statement makes it clear that there are two distinct situations, which need to be handled separately.




            Compiler warning for statement on same line as #endif
            Asked 2021-Dec-20 at 18:30

            Consider code:



            Answered 2021-Dec-20 at 18:30

            There's compiler warning C4067. It looks like you need to set the flag /Za for it to apply to #endif directives.

            In the Visual Studio properties page, this flag is controlled by the setting "Disable Language Extensions" in the Language subsection of the C/C++ section.



            Ping Tasks will not complete
            Asked 2021-Nov-30 at 13:11

            I am working on a "heartbeat" application that pings hundreds of IP addresses every minute via a loop. The IP addresses are stored in a list of a class Machines. I have a loop that creates a Task (where MachinePingResults is basically a Tuple of an IP and online status) for each IP and calls a ping function using System.Net.NetworkInformation.

            The issue I'm having is that after hours (or days) of running, one of the loops of the main program fails to finish the Tasks which is leading to a memory leak. I cannot determine why my Tasks are not finishing (if I look in the Task list during runtime after a few days of running, there are hundreds of tasks that appear as "awaiting"). Most of the time all the tasks finish and are disposed; it is just randomly that they don't finish. For example, the past 24 hours had one issue at about 12 hours in with 148 awaiting tasks that never finished. Due to the nature of not being able to see why the Ping is hanging (since it's internal to .NET), I haven't been able to replicate the issue to debug.

            (It appears that the Ping call in .NET can hang and the built-in timeout fail if there is a DNS issue, which is why I built an additional timeout in)

            I have a way to cancel the main loop if the pings don't return within 15 seconds using Task.Delay and a CancellationToken. Then in each Ping function I have a Delay in case the Ping call itself hangs that forces the function to complete. Also note I am only pinging IPv4; there is no IPv6 or URL.

            Main Loop



            Answered 2021-Nov-26 at 08:37

            There are quite a few gaps in the code posted, but I attempted to replicate and in doing so ended up refactoring a bit.

            This version seems pretty robust, with the actual call to SendAsync wrapped in an adapter class.

            I accept this doesn't necessarily answer the question directly, but in the absence of being able to replicate your problem exactly, offers an alternative way of structuring the code that may eliminate the problem.



            What's the whole point of a JWT refresh token?
            Asked 2021-Nov-02 at 19:38

            I've been reading about this for a while, and nothing makes sense, and the explanations are conflicting, and the comments are proving that.

            So far what I understood is that JWTs are storing information encoded by the server, can have expiry times, and the server with its secret key can decode the information in it if it's valid. Makes sense.

            It is useful for scalability, so independent APIs can decode, and validate the information in the token, as long as they have the secret key. Also, there's no need for the information to be stored in any database, not like in sessions. Makes sense.

            If the token gets stolen, the API has no way to tell if the token is used by the right person, or not. It is the downside of the above.

            By reducing the expiry time of a token, the security vulnerability can be reduced, so thieves have less time to use the tokens without permission. (side question, but if they were able to steal it once, they will probably do it second time as well)

            But reducing the time of how long the token is valid means that the user will need to log in every time the token expires, and as from above, it's quite frequent, so wouldn't provide too good UX. Makes sense.

            From now, nothing makes sense:

            Introducing a refresh token would solve this problem, because it has a longer expiry time. With the refresh token access tokens can be generated, so the user can be logged in as long as they have the refresh token - which is for a longer period of time -, while a stolen access token is still only valid for a short time.

            For me the above seems like an extra layer of complexity without any improvement in security. I.e. for me it seems like the above equals to a long-living access token.

            Why? Because for me it seems the refresh token is basically an access token (because that's what it generates). So having the refresh token means unlimited access tokens, so unlimited access to the API.

            Then I have a read an answer that there's a one-to-one mapping of refresh token, and access token, so stealing the access token still means unauthorised access to the API, but only for a short time, and stealing the refresh token would generate a different access token, so the API could detect the anomaly (different access tokens are used for the same account), invalidating the access tokens.

            It seems like I'm not the only one who's confused about the question.

            If the above is not true, how refresh tokens really help?

            If the above is true, and there really is one-to-one mapping of refresh tokens, and access tokens:

            • it completely loses it's benefit of being "stateless"
            • the user cannot be logged in from multiple devices (it would have been an "anomaly")
            • I can't understand how an access token could be invalidated - is there a session ID stored in the token data, or the user is "blocked"?

            It would have been really great if someone could clear the question, because from 5 explanations, 5 conflicting statements are (sometimes the same explanation contains conflicting information), and many developers want to understand this method.



            Answered 2021-Nov-02 at 19:38

            There is this general confusion around token-based auth, so let's try to clear some of it up.

            First, JWTs are not just "encoded" by the server, they are "signed" (which more precisely is message authentication usually). The purpose is that such a token can not be altered or changed by the client, any field (claim) in the token can be trusted to be as the issuer created it, otherwise validation will fail.

            This yields two important takeaways:

            • validating tokens is important (obviously) in any implementation
            • the contents (claims) of a JWT are not encrypted, ie. it's not a secret and can be viewed by the client

            Such a token can be used to maintain a session without server-side state, if it contains some kind of an identity for the subject (user, like a user id or email address), and an expiry.

            Another important takeaway though:

            • Logout (immediate session invalidation) is not possible in a stateless way, which is a drawback. To be able to log out as in invalidate an existing session, the server must store and check revoked tokens, which is necessarily a stateful operation.

            Also a JWT token is typically stored in a way that it's accessible for client-side code (javascript), so things like who the user is and when the token will expire can be read by the client app. It need not be so, yet most implementations do this, eg. store it in localstorage. This makes these tokens susceptible to XSS attacks, meaning that any successful XSS will be able to get the token.

            For the reasons discussed so far, JWT authentication is inherently less secure than a plain old session, and should only be used if there is a need. Many times when token auth is used, it is not actually necessary, just fancy.

            Sometimes such a token is stored in a httpOnly cookie, but in that case the token cannot be sent to multiple origins (one benefit of localStorage) and a plain old session id could also have been used, and would actually be more secure.

            Ok, so what are refresh tokens. As you correctly stated, limiting the lifetime of an access token is useful to limit the validity of a compromised token. So a refresh token can be used to get a new access token when the old one expired. The key is where these are stored.

            A key takeaway:

            • If a refresh token is stored the same way as the access token, it usually doesn't make any sense. This is a common mistake in implementations.

            In a better architecture, the following can happen:

            • There are (both logically and "physically" as much as it makes sense in today's cloud world) at least two separate components: the identity provider (IdP, or "login service"), and the resource server (eg. an API).
            • When a user logs in, they actually create a session with the IdP. In this case either a plain old session id (acting as refresh token) or an actual JWT refresh token is set up for the IdP origin (domain name).
            • An access token is then created when needed for the resource server origin, using the existing session with the identity provider.
            • Now even if there is a total compromise of the resource server, like in case of successful XSS, the refresh token belongs to a completely separate origin, so cannot be accessed by the attacker. Even if it's the same origin, but the refresh token is in a httpOnly cookie, that helps, because the attacker then needs to be able to perform repeated XSS against a victim user to receive new access tokens.

            There can be implementation variants of this, but the point is the above, separation of access to the two tokens.

            A one-to-one mapping of refresh tokens to access tokens as you described would I think be unusual and also unnecessary, but one session per user is in fact sometimes a requirement (especially in financial applications where you want to have a very clear audit trail of what a user did). But this is not much related to the things discussed above.

            Also as stated above, proper logout (session invalidation) is not possible in a stateless way. Fortunately, very few applications actually need to be truly stateless on the server-side.


            Community Discussions, Code Snippets contain sources that include Stack Exchange Network


            No vulnerabilities reported

            Install Tokens

            You can download it from GitHub.


            Pull requests are welcome! Please keep standards discussions to the EIP repos. When submitting a pull request, please do so to the staging branch. For a pull request to be accepted, they must pass the test suite. If a pull request adds features, it should add test coverage for those features.
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