在用Taro写头像上传功能时，因为需要对获得的图片进行剪切成圆形或方形。使用组件剪切完之后返回的是一个本地图片的相对路径。这个时候我们就需要自己实现将本地路径重新转换为二进制文件。

引入两个js文件

mimeMap.js

module.exports = {"0.001": "application/x-001","0.323": "text/h323","0.907": "drawing/907",".acp": "audio/x-mei-aac",".aif": "audio/aiff",".aiff": "audio/aiff",".asa": "text/asa",".asp": "text/asp",".au": "audio/basic",".awf": "application/vnd.adobe.workflow",".bmp": "application/x-bmp",".c4t": "application/x-c4t",".cal": "application/x-cals",".cdf": "application/x-netcdf",".cel": "application/x-cel",".cg4": "application/x-g4",".cit": "application/x-cit",".cml": "text/xml",".cmx": "application/x-cmx",".crl": "application/pkix-crl",".csi": "application/x-csi",".cut": "application/x-cut",".dbm": "application/x-dbm",".dcd": "text/xml",".der": "application/x-x509-ca-cert",".dib": "application/x-dib",".doc": "application/msword",".drw": "application/x-drw",".dwf": "Model/vnd.dwf",".dwg": "application/x-dwg",".dxf": "application/x-dxf",".emf": "application/x-emf",".ent": "text/xml",".eps": "application/x-ps",".etd": "application/x-ebx",".fax": "image/fax",".fif": "application/fractals",".frm": "application/x-frm",".gbr": "application/x-gbr",".gif": "image/gif",".gp4": "application/x-gp4",".hmr": "application/x-hmr",".hpl": "application/x-hpl",".hrf": "application/x-hrf",".htc": "text/x-component",".html": "text/html",".htx": "text/html",".ico": "image/x-icon",".iff": "application/x-iff",".igs": "application/x-igs",".img": "application/x-img",".isp": "application/x-internet-signup",".java": "java/*",".jpe": "image/jpeg",".jpeg": "image/jpeg",".jpg": "application/x-jpg",".jsp": "text/html",".lar": "application/x-laplayer-reg",".lavs": "audio/x-liquid-secure",".lmsff": "audio/x-la-lms",".ltr": "application/x-ltr",".m2v": "video/x-mpeg",".m4e": "video/mpeg4",".man": "application/x-troff-man",".mdb": "application/msaccess",".mfp": "application/x-shockwave-flash",".mhtml": "message/rfc822",".mid": "audio/mid",".mil": "application/x-mil",".mnd": "audio/x-musicnet-download",".mocha": "application/x-javascript",".mp1": "audio/mp1",".mp2v": "video/mpeg",".mp4": "video/mpeg4",".mpd": "application/vnd.ms-project",".mpeg": "video/mpg",".mpga": "audio/rn-mpeg",".mps": "video/x-mpeg",".mpv": "video/mpg",".mpw": "application/vnd.ms-project",".mtx": "text/xml",".net": "image/pnetvue",".nws": "message/rfc822",".out": "application/x-out",".p12": "application/x-pkcs12",".p7c": "application/pkcs7-mime",".p7r": "application/x-pkcs7-certreqresp",".pc5": "application/x-pc5",".pcl": "application/x-pcl",".pdf": "application/pdf",".pdx": "application/vnd.adobe.pdx",".pgl": "application/x-pgl",".pko": "application/vnd.ms-pki.pko",".plg": "text/html",".plt": "application/x-plt",".png": "application/x-png",".ppa": "application/vnd.ms-powerpoint",".pps": "application/vnd.ms-powerpoint",".ppt": "application/x-ppt",".prf": "application/pics-rules",".prt": "application/x-prt",".ps": "application/postscript",".pwz": "application/vnd.ms-powerpoint",".ra": "audio/vnd.rn-realaudio",".ras": "application/x-ras",".rdf": "text/xml",".red": "application/x-red",".rjs": "application/vnd.rn-realsystem-rjs",".rlc": "application/x-rlc",".rm": "application/vnd.rn-realmedia",".rmi": "audio/mid",".rmm": "audio/x-pn-realaudio",".rms": "application/vnd.rn-realmedia-secure",".rmx": "application/vnd.rn-realsystem-rmx",".rp": "image/vnd.rn-realpix",".rsml": "application/vnd.rn-rsml",".rtf": "application/msword",".rv": "video/vnd.rn-realvideo",".sat": "application/x-sat",".sdw": "application/x-sdw",".slb": "application/x-slb",".slk": "drawing/x-slk",".smil": "application/smil",".snd": "audio/basic",".sor": "text/plain",".spl": "application/futuresplash",".ssm": "application/streamingmedia",".stl": "application/vnd.ms-pki.stl",".sty": "application/x-sty",".swf": "application/x-shockwave-flash",".tg4": "application/x-tg4",".tif": "image/tiff",".tiff": "image/tiff",".top": "drawing/x-top",".tsd": "text/xml",".uin": "application/x-icq",".vcf": "text/x-vcard",".vdx": "application/vnd.visio",".vpg": "application/x-vpeg005",".vsd": "application/x-vsd",".vst": "application/vnd.visio",".vsw": "application/vnd.visio",".vtx": "application/vnd.visio",".wav": "audio/wav",".wb1": "application/x-wb1",".wb3": "application/x-wb3",".wiz": "application/msword",".wk4": "application/x-wk4",".wks": "application/x-wks",".wma": "audio/x-ms-wma",".wmf": "application/x-wmf",".wmv": "video/x-ms-wmv",".wmz": "application/x-ms-wmz",".wpd": "application/x-wpd",".wpl": "application/vnd.ms-wpl",".wr1": "application/x-wr1",".wrk": "application/x-wrk",".ws2": "application/x-ws",".wsdl": "text/xml",".xdp": "application/vnd.adobe.xdp",".xfd": "application/vnd.adobe.xfd",".xhtml": "text/html",".xls": "application/x-xls",".xml": "text/xml",".xq": "text/xml",".xquery": "text/xml",".xsl": "text/xml",".xwd": "application/x-xwd",".sis": "application/vnd.symbian.install",".x_t": "application/x-x_t",".apk": "application/vnd.android.package-archive","0.301": "application/x-301","0.906": "application/x-906",".a11": "application/x-a11",".ai": "application/postscript",".aifc": "audio/aiff",".anv": "application/x-anv",".asf": "video/x-ms-asf",".asx": "video/x-ms-asf",".avi": "video/avi",".biz": "text/xml",".bot": "application/x-bot",".c90": "application/x-c90",".cat": "application/vnd.ms-pki.seccat",".cdr": "application/x-cdr",".cer": "application/x-x509-ca-cert",".cgm": "application/x-cgm",".class": "java/*",".cmp": "application/x-cmp",".cot": "application/x-cot",".crt": "application/x-x509-ca-cert",".css": "text/css",".dbf": "application/x-dbf",".dbx": "application/x-dbx",".dcx": "application/x-dcx",".dgn": "application/x-dgn",".dll": "application/x-msdownload",".dot": "application/msword",".dtd": "text/xml",".dwf": "application/x-dwf",".dxb": "application/x-dxb",".edn": "application/vnd.adobe.edn",".eml": "message/rfc822",".epi": "application/x-epi",".eps": "application/postscript",".exe": "application/x-msdownload",".fdf": "application/vnd.fdf",".fo": "text/xml",".g4": "application/x-g4",".tif": "image/tiff",".gl2": "application/x-gl2",".hgl": "application/x-hgl",".hpg": "application/x-hpgl",".hqx": "application/mac-binhex40",".hta": "application/hta",".htm": "text/html",".htt": "text/webviewhtml",".icb": "application/x-icb",".ico": "application/x-ico",".ig4": "application/x-g4",".iii": "application/x-iphone",".ins": "application/x-internet-signup",".IVF": "video/x-ivf",".jfif": "image/jpeg",".jpe": "application/x-jpe",".jpg": "image/jpeg",".js": "application/x-javascript",".la1": "audio/x-liquid-file",".latex": "application/x-latex",".lbm": "application/x-lbm",".ls": "application/x-javascript",".m1v": "video/x-mpeg",".m3u": "audio/mpegurl",".mac": "application/x-mac",".math": "text/xml",".mdb": "application/x-mdb",".mht": "message/rfc822",".mi": "application/x-mi",".midi": "audio/mid",".mml": "text/xml",".mns": "audio/x-musicnet-stream",".movie": "video/x-sgi-movie",".mp2": "audio/mp2",".mp3": "audio/mp3",".mpa": "video/x-mpg",".mpe": "video/x-mpeg",".mpg": "video/mpg",".mpp": "application/vnd.ms-project",".mpt": "application/vnd.ms-project",".mpv2": "video/mpeg",".mpx": "application/vnd.ms-project",".mxp": "application/x-mmxp",".nrf": "application/x-nrf",".odc": "text/x-ms-odc",".p10": "application/pkcs10",".p7b": "application/x-pkcs7-certificates",".p7m": "application/pkcs7-mime",".p7s": "application/pkcs7-signature",".pci": "application/x-pci",".pcx": "application/x-pcx",".pdf": "application/pdf",".pfx": "application/x-pkcs12",".pic": "application/x-pic",".pl": "application/x-perl",".pls": "audio/scpls",".png": "image/png",".pot": "application/vnd.ms-powerpoint",".ppm": "application/x-ppm",".ppt": "application/vnd.ms-powerpoint",".pr": "application/x-pr",".prn": "application/x-prn",".ps": "application/x-ps",".ptn": "application/x-ptn",".r3t": "text/vnd.rn-realtext3d",".ram": "audio/x-pn-realaudio",".rat": "application/rat-file",".rec": "application/vnd.rn-recording",".rgb": "application/x-rgb",".rjt": "application/vnd.rn-realsystem-rjt",".rle": "application/x-rle",".rmf": "application/vnd.adobe.rmf",".rmj": "application/vnd.rn-realsystem-rmj",".rmp": "application/vnd.rn-rn_music_package",".rmvb": "application/vnd.rn-realmedia-vbr",".rnx": "application/vnd.rn-realplayer",".rpm": "audio/x-pn-realaudio-plugin",".rt": "text/vnd.rn-realtext",".rtf": "application/x-rtf",".sam": "application/x-sam",".sdp": "application/sdp",".sit": "application/x-stuffit",".sld": "application/x-sld",".smi": "application/smil",".smk": "application/x-smk",".sol": "text/plain",".spc": "application/x-pkcs7-certificates",".spp": "text/xml",".sst": "application/vnd.ms-pki.certstore",".stm": "text/html",".svg": "text/xml",".tdf": "application/x-tdf",".tga": "application/x-tga",".tif": "application/x-tif",".tld": "text/xml",".torrent": "application/x-bittorrent",".txt": "text/plain",".uls": "text/iuls",".vda": "application/x-vda",".vml": "text/xml",".vsd": "application/vnd.visio",".vss": "application/vnd.visio",".vst": "application/x-vst",".vsx": "application/vnd.visio",".vxml": "text/xml",".wax": "audio/x-ms-wax",".wb2": "application/x-wb2",".wbmp": "image/vnd.wap.wbmp",".wk3": "application/x-wk3",".wkq": "application/x-wkq",".wm": "video/x-ms-wm",".wmd": "application/x-ms-wmd",".wml": "text/vnd.wap.wml",".wmx": "video/x-ms-wmx",".wp6": "application/x-wp6",".wpg": "application/x-wpg",".wq1": "application/x-wq1",".wri": "application/x-wri",".ws": "application/x-ws",".wsc": "text/scriptlet",".wvx": "video/x-ms-wvx",".xdr": "text/xml",".xfdf": "application/vnd.adobe.xfdf",".xls": "application/vnd.ms-excel",".xlw": "application/x-xlw",".xpl": "audio/scpls",".xql": "text/xml",".xsd": "text/xml",".xslt": "text/xml",".x_b": "application/x-x_b",".sisx": "application/vnd.symbian.install",".ipa": "application/vnd.iphone",".xap": "application/x-silverlight-app",".zip": "application/x-zip-compressed",
}

fromdata.js

const mimeMap = require('./mimeMap.js')function FormData() {let fileManager = wx.getFileSystemManager();// 获取小程序的文件系统管理器let data = {};// 存储普通表单字段的键值对let files = [];// 存储文件表单字段的信息// 添加普通表单字段this.append = (name, value) => {data[name] = value;return true;}// 添加文件表单字段this.appendFile = (name, path, fileName) => {let buffer = fileManager.readFileSync(path); // 读取文件内容到 bufferif (Object.prototype.toString.call(buffer).indexOf("ArrayBuffer") < 0) {return false;// 如果不是 ArrayBuffer 类型，返回 false}if (!fileName) {fileName = getFileNameFromPath(path);// 如果没有指定文件名，从路径中获取}files.push({name: name,buffer: buffer,fileName: fileName});return true;}// 获取最终的表单数据this.getData = () => convert(data, files)
}function getFileNameFromPath(path) {let idx = path.lastIndexOf("/");return path.substr(idx + 1);
}function convert(data, files) {let boundaryKey = 'wxmpFormBoundary'; // 数据分割符，一般是随机的字符串let boundary = '--' + boundaryKey;let endBoundary = boundary + '--';let postArray = [];//拼接参数if (data && Object.prototype.toString.call(data) == "[object Object]") {for (let key in data) {postArray = postArray.concat(formDataArray(boundary, key, data[key]));}}//拼接文件if (files && Object.prototype.toString.call(files) == "[object Array]") {for (let i in files) {let file = files[i];postArray = postArray.concat(formDataArray(boundary, file.name, file.buffer, file.fileName));}}//结尾let endBoundaryArray = [];endBoundaryArray.push(...endBoundary.toUtf8Bytes());postArray = postArray.concat(endBoundaryArray);return {contentType: 'multipart/form-data; boundary=' + boundaryKey,buffer: new Uint8Array(postArray).buffer}
}function randString() {var result = '';var chars = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'for (var i = 17; i > 0; --i) result += chars[Math.floor(Math.random() * chars.length)];return result;
}function formDataArray(boundary, name, value, fileName) {let dataString = '';let isFile = !!fileName;dataString += boundary + '\r\n';dataString += 'Content-Disposition: form-data; name="' + name + '"';if (isFile) {dataString += '; filename="' + fileName + '"' + '\r\n';dataString += 'Content-Type: ' + getFileMime(fileName) + '\r\n\r\n';}else {dataString += '\r\n\r\n';dataString += value;}var dataArray = [];dataArray.push(...dataString.toUtf8Bytes());if (isFile) {let fileArray = new Uint8Array(value);dataArray = dataArray.concat(Array.prototype.slice.call(fileArray));}dataArray.push(..."\r".toUtf8Bytes());dataArray.push(..."\n".toUtf8Bytes());return dataArray;
}function getFileMime(fileName) {let idx = fileName.lastIndexOf(".");let mime = mimeMap[fileName.substr(idx)];return mime ? mime : "application/octet-stream"
}String.prototype.toUtf8Bytes = function () {var str = this;var bytes = [];for (var i = 0; i < str.length; i++) {bytes.push(...str.utf8CodeAt(i));if (str.codePointAt(i) > 0xffff) {i++;}}return bytes;
}String.prototype.utf8CodeAt = function (i) {var str = this;var out = [], p = 0;var c = str.charCodeAt(i);if (c < 128) {out[p++] = c;} else if (c < 2048) {out[p++] = (c >> 6) | 192;out[p++] = (c & 63) | 128;} else if (((c & 0xFC00) == 0xD800) && (i + 1) < str.length &&((str.charCodeAt(i + 1) & 0xFC00) == 0xDC00)) {// Surrogate Pairc = 0x10000 + ((c & 0x03FF) << 10) + (str.charCodeAt(++i) & 0x03FF);out[p++] = (c >> 18) | 240;out[p++] = ((c >> 12) & 63) | 128;out[p++] = ((c >> 6) & 63) | 128;out[p++] = (c & 63) | 128;} else {out[p++] = (c >> 12) | 224;out[p++] = ((c >> 6) & 63) | 128;out[p++] = (c & 63) | 128;}return out;
};module.exports = FormData;

这两个js文件引入之后就可以直接 使用转换了

具体代码使用

import FormData from "../../../../utils/formdata";//调用方法
const cutImage = async (data: any) => {   //data为图片路径const formData = new FormData();//根据自己引入的文件，创建了一个新的 FormData 对象formData.appendFile("imgs", data, "test.png");//将一个文件数据添加到 FormData 对象中。const convertData = formData.getData();const requst = axios.create({baseURL: "http://-----------:8000",timeout: 10000,headers: {"Content-Type": "multipart/form-data; boundary=wxmpFormBoundary",},adapter: TaroAdapter, // 添加这一行替换默认的适配器});const res = await requst.post("/api/v1/oss", convertData.buffer);
}

这样就可以正常上传了。

重点：

咱们这是自己伪造的FormData，虽然结果全部相等。但是也需要后端进行处理一下，不能直接使用，需要后端进行一下转换。