Question

var saved = new Date();
setTimeout(() => console.log(saved, new Date()), 1000);
setTimeout(() => console.log(saved, new Date()), 2000);

在任何javascript引擎上执行此原始脚本，您将看到这样的输出（查看秒数）：

2018-02-21T22:50:29.066Z 2018-02-21T22:50:30.071Z
2018-02-21T22:50:29.066Z 2018-02-21T22:50:31.070Z

第一列中的所有日期都相同（因为它是唯一的SAVED日期）。

但是如果您在Google应用脚本中执行类似的脚本：

///// code.gs /////

function doGet() { // a main window maker
  return HtmlService.createTemplateFromFile('index').evaluate();
}

var saved = new Date(); // <<< our hero

function getDates() {
  return JSON.stringify({saved: saved, now: new Date()});


///// index.html /////

look at your browser console
<script>
setTimeout(() => google.script.run
  .withSuccessHandler(console.log)
  .getDates()
  , 1000);
setTimeout(() => google.script.run
  .withSuccessHandler(console.log)
  .getDates()
  , 2000);
</script>

你会看到这样的输出（看秒）：

{"saved":"2018-02-21T23:03:58.663Z","now":"2018-02-21T23:03:58.664Z"}
{"saved":"2018-02-21T23:03:59.655Z","now":"2018-02-21T23:03:59.656Z"}

每当您通过google.script.run从客户端调用服务器脚本时，变量saved正在更新!!!

怎么了？我怎么能避免这个？

Answer 1

Google Script中的运行之间没有任何内容。从这个意义上说，这是一个预期的结果。它必须设置一个新的getDates()值，否则在函数saved内部甚至不会声明变量.setHours()。如果您希望实际存储一个值用于多次运行，则需要使用PropertiesService或使用#include <CoreFoundation/CoreFoundation.h> #include <Security/Security.h> #ifdef __cplusplus #include <vector> #else // C #include <stdbool.h> // For adding boolean support #endif // __cplusplus // Convenience define for cleanup #define _CLEANUP_IF(a) if ((a)) goto Cleanup; #ifdef __cplusplus // Wrap into class in case of C++ class Sha256Calculator { public: #endif // __cplusplus // Calculates SHA256 hash from given array of data and returns array // Note: Parameter "outHash" is manually allocated so consider calling free(outHash) after using it static bool calculateSha256(uint8_t** outHash, size_t* outHashSize, const uint8_t *data, const size_t dataSize) { bool result = false; CFErrorRef error = NULL; SecTransformRef digestTransform = NULL; CFDataRef sourceData = NULL; CFDataRef outDataRef = NULL; const UInt8 * outData = NULL; CFIndex outDataSize = 0; // Create a CFData object from the source sourceData = CFDataCreate(kCFAllocatorDefault, (const UInt8*)data, dataSize); _CLEANUP_IF(!sourceData); digestTransform = SecDigestTransformCreate(kSecDigestSHA2, 256, &error); _CLEANUP_IF(error); SecTransformSetAttribute(digestTransform, kSecTransformInputAttributeName, (CFDataRef)sourceData, &error); _CLEANUP_IF(error); outDataRef = (CFDataRef)SecTransformExecute(digestTransform, &error); _CLEANUP_IF(error); _CLEANUP_IF(!outDataRef); // Extract data from CFDataRef to array outData = CFDataGetBytePtr(outDataRef); // Returns read-only (UInt8*) pointer to the data outDataSize = CFDataGetLength(outDataRef); if (outHash) { *outHash = (uint8_t*)malloc(outDataSize); if (*outHash) { memcpy(*outHash, outData, outDataSize); if (outHashSize) { *outHashSize = (size_t)outDataSize; } result = true; } } // Notes: // * All the objects are released except "outData" since it's handled and cleaned by using outDataRef // * CFRelease throws error if the passed object is NULL, so check objects before releasing Cleanup: // Use CFShow(error) for getting details about error if (error) { CFRelease(error); } if (digestTransform) { CFRelease(digestTransform); } if (sourceData) { CFRelease(sourceData); } if (outDataRef) { CFRelease(outDataRef); } return result; } #ifdef __cplusplus // Convenience method for cpp using vectors static bool calculateSha256(std::vector<uint8_t>& outHash, const std::vector<uint8_t>& data) { // Call original method uint8_t * outHashArray = nullptr; size_t outHashSize; bool result; result = calculateSha256(&outHashArray, &outHashSize, data.data(), data.size()); if (!result) return false; // Put resulting array in vector outHash.clear(); outHash.insert(outHash.end(), &outHashArray[0], &outHashArray[outHashSize]); // Clean allocated array if (outHashArray) free(outHashArray); return result; } }; #endif // __cplusplus设置实际设置值，依此类推。

google.script.run调用整个服务器脚本而不是函数？为什么？

1 个答案: